Incidence Of False-negative Results Research Articles

False-Negative Centromere 15 Probe Results in Association with African Ancestry in Plasma Cell Dyscrasias

Purpose:Multiple myeloma (MM) is a plasma cell (PC) malignancy with an increasing incidence in the United States. Fluorescence in situ hybridization (FISH) is currently the gold-standard diagnostic assay to detect recurrent genomic abnormalities of prognostic and therapeutic significance in MM. Hyperdiploid MM, a standard risk abnormality, is characterized by gains of odd-numbered chromosomes including chromosome 15. While gains of chromosome 15 have been reported in approximately 53% of standard risk MM patients (Chretien, Blood, 2015), losses of chromosome 15 are rarely reported. Enumeration of chromosome 15 centromere is detected using the alpha satellite FISH probe. We previously discovered ~9% of cases had false-negative chromosome 15 FISH results when compared to Mate Pair Sequencing (MPseq) (Smadbeck, BCJ, 2019). To our knowledge, no previous studies have reported a reduced performance of the alpha satellite D15Z4 FISH probe in PC FISH studies. A false-negative result for D15Z4 could result in an underreporting of trisomy 15 and overreporting of monosomy 15. Here, we investigated the incidence of false-negative D15Z4 FISH results by examining the presence of monosomy 15 from patients with a monoclonal gammopathy.Methods:We identified 1231 samples from patients with a monoclonal gammopathy who had undergone uniform testing to identify MM-specific cytogenetic abnormalities. DNA from bone marrow samples was genotyped on the Precision Medicine Research Array and biogeographical ancestry was assessed using the Geographic Population Structure Origins tool (Elhaik, Nat Commun, 2014; Home DNA 2016). FISH of immunoglobulin (cIg)-stained PCs was performed as described (Baughn, BCJ, 2018). Chromosome 15 centromere probe (Vysis CEP 15 D15Z4, Abbott Molecular, Abbott Park, IL) was used for chromosome 15 enumeration. Samples were divided into two groups: Cases with or without evidence of monosomy 15 by FISH. Mann-Whitney U test was applied to compare difference between groups for data deviating from normal distribution. A Chi-squared test evaluating the differences across these two groups was used.Results:We identified monosomy 15 in 31 cases (2.5% of cohort). Monosomy 15 was observed in nearly 100% of both the PC (cIg+) and non-PC (cIg-) populations, by contrast to the other recurrent PC-specific genomic abnormalities which were restricted to only the PC population. All samples with a banded analysis revealed most metaphases had two normal chromosome 15s demonstrating that the D15Z4 FISH probe failed to correctly enumerate the number of chromosome 15 centromere signals. Of the samples with a monosomy 15 result, the median African ancestry was 76.2% (95% percentiles: 77.5%-89.0%), while the median African ancestry of the non-monosomy 15 cohort was 2.3% (95% percentiles: 0%-87.7%) (). Although not all patients with >50% African ancestry had evidence of monosomy 15, 26/31 (83.9%) of patients with monosomy 15 had >50% African ancestry. Accordingly, patients with African ancestry (similarity ≥ 0.70) had 8.02-fold (95% confidence interval: 3.73-17.25, P = 9.92 X10 -8) increased possibility to have monosomy 15. Of cases with monosomy 15, 22 (71.0%) had an IGH rearrangement with the most prevalent IGH partner being CCND1. The incidence of t(11;14) was greater in the monosomy 15 group (13/31:41.9%), in contrast to the non-monosomy 15 group (330/1200=27.5%) (P = 0.12).Conclusions:We report a polymorphic variant of the chromosome 15 centromere resulting in a false-negative FISH result using the D15Z4 FISH probe. Surprisingly, the false-negative FISH result was not uniformly distributed among patients and was highly enriched in individuals of African ancestry. This may be due to a variation of the chromosome 15 alpha satellite in some individuals that prevents the D15Z4 FISH probe from sufficiently binding (O'Keefe, Genome Research, 2000). Although this study focused on identification of monosomy 15, the incidence of a false-negative result is likely greater than we have reported in this study since we did not evaluate cases that had a true trisomy 15 that was reported as normal chromosome 15 enumeration by FISH. This study highlights a critical need to ensure diagnostic reagents have equal performance for all patients independent of their ancestry. Evaluation of genomic events using unbiased approaches such as whole genome sequencing may circumvent some of these limitations. DisclosuresElhaik: DDC: Consultancy. Baird: DDC: Current Employment. Kumar: Antengene: Consultancy, Honoraria; Bluebird Bio: Consultancy; Beigene: Consultancy; BMS: Consultancy, Research Funding; Tenebio: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Novartis: Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche-Genentech: Consultancy, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy; Carsgen: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding.

Molecular Analysis of Liquid-Based Cytological Specimen Using Virtually Positive Sputum with Adenocarcinoma Cells.

Liquid-based cytology (LBC) analysis of sputum is a useful diagnostic and prognostic tool for detecting lung cancer. DNA and RNA derived from lung cancer cells can be used for this diagnosis. However, the quality of cytological material is not always adequate for molecular analysis due to the effect of formalin in the commercially available fixation kits. In this study, we examined DNA and RNA extraction methods for LBC analysis with formalin fixation, using lung carcinoma cell lines and sputum. The human non-small cell lung cancer cell lines were fixed with LBC fixation reagents, such as CytoRich red preservative. Quantification of thyroid transcription factor-1 (TTF-1) and actin mRNA, epidermal growth factor receptor (EGFR) DNA in HCC827, H1975, and H1299 cells, and mutation analysis of EGFR in HCC827 and H1975 cells were performed by quantitative PCR (qPCR) and fluorescence resonance energy transfer (FRET)-based preferential homoduplex formation assay (F-PHFA) method, respectively. mRNA and DNA extracted from cell lines using RNA and/or DNA extraction kits for formalin-fixed paraffin-embedded (FFPE) fixed with various LBC solutions were efficiently detected by qPCR. The detection limit of EGFR mutations was at a rate of 5% mutated positive cells in LBC. The detection limit of the EGFR exon 19 deletion in HCC827 was detected in more than 1.5% of the positive cells in sputum. In contrast, the detection limit of the T790M/L858R mutation in H1975 was detected in more than 13% of the positive cells. We also detected EGFR mutations using next generation sequencing (NGS). The detection limit of NGS for EGFR mutation was lower than that of the F-PHFA method. Furthermore, more than 0.1% of positive cells could be cytomorphologically detected. Our results demonstrate that LBC systems are powerful tools for cytopathological and genetic analyses. However, careful attention should be paid to the incidence of false negative results in the genetic analysis of EGFR mutations detected by LBC.

Features of in vivo diagnostics of delayed drug hypersensitivity to beta-lactams

Background. Beta-lactams are the most widely used group of antibacterial agents. They are used for treating of infectious complications of varying severity, including urgent situations. The exclusion of the entire beta-lactam group not only leads to a significant increase in the cost of treatment, length of hospitalization and the formation of resistance of the flora to alternative antibiotics, but also may be life threatening in some cases. Therefore, correct diagnosis and establishement of the offending medication can prevent the development of allergic reactions and to avoid unreasonable lifelong bans on the use of certain medications, which often lead to a decrease of the effectiveness of treatment and increase its cost. The aim of the study was to develop the diagnostic and management algorithm and of of patients with presumptive diagnosis of delayed drug hypersensitivity to beta-lactams. Materials and methods. A comprehensive in-depth examination, including in vivo tests with beta-lactams was done in 53 patients (37 - 70% women, and 16 - 30% men) with a presumptive diagnosis of delayed drug hypersensitivity to beta-lactams. The minimum age at the time of the reaction was 4 years, the maximum age was 86 years, the average age was 37 years,the median was 38,5 years old. The minimum age at the time of testing was 6 years, the maximum age was 89 years, the average age was 44 years, median was 44 years old. Results. In the group of patients with delayed drug hypersensitivity to beta-lactams (n=21) the diagnosis was confirmed by skin testing in 19 (90,5%) patients, in 18 (85,7%) to aminopenicillins, and 1 (4,8%) to ceftriaxone. In 2 (9,5%) cases, the diagnosis was established using a drug provocation test: for amoxicillin (4,8%) and for ceftriaxone (4,8%). According to the obtained data, the specificity of skin tests for the diagnostics of delayed drug hypersensitivity to beta-lactams was 100%. In case of delayed drug hypersensitivity to aminopenicillins, the sensitivity of skin tests was 94,7%, the negative predictive value of skin tests was 93,7%, the overall accuracy of skin testing was 97%, and the incidence of false-negative results was 5,3%. Conclusion. Skin testing is promising and safe in the diagnositics of delayed drug hypersensitivity to beta-lactams. It allows to exclude unreasonable contraindications for the use of beta-lactams, thereby increasing the effectiveness of treatment while reducing economic costs.

Accuracy of Sentinel Lymph Node Biopsy after Neoadjuvant Chemotherapy in Breast Cancer Patients; Single Center Experience

Purpose: Most important factor affecting prognosis of breast cancer is axillary nodal involvement. Several studies evaluated the accuracy of Sentinel lymph node biopsy in breast cancer patients post neoadjuvant chemotherapy. In this study, we will examine accuracy and feasibility of using Sentinel lymph node biopsy in predicting axillary lymph node status in breast cancer patients after neoadjuvant chemotherapy. Methods: 45 female patients with resectable, nonmetastatic breast carcinoma cases who received neoadjuvant chemotherapy were enrolled in this study according to the routine Mansoura Oncology Center—guidelines of management of breast cancer. Methylene blue dye used for detection of Sentinel lymph node. Results: Successful Sentinel lymph node detection was 82.2%. Skin involvement (T4 disease) were linked to a low identification (P = 0.005). False negative rate equals 11/27 = (40.7%).With advancement of the stage of the tumor, the incidence of false negative results increases significantly (p = 0.012) with 95% confidence interval; 1.2 - 5.4. Conclusion: Sentinel lymph node should be adopted to be the standard method for axillary staging with T1-3 tumors after receiving neoadjuvant chemotherapy, in T4 patients, it is associated with low detection rate & high false negative rate making it doubtful technique for axillary staging.

Comparison of CK-IHC assay on serial frozen sections, the OSNA assay, and in combination for intraoperative evaluation of SLN metastases in breast cancer

BackgroundIntraoperative evaluations of sentinel lymph node (SLN) metastases are performed for providing appropriate and immediate axillary treatments in breast cancer patients who do not meet Z0011 criteria; however, standard intraoperative procedure has not yet been established.MethodsWe consecutively performed intraoperative evaluation for SLN metastases using both a cytokeratin immunohistochemistry (CK-IHC) assay on serial frozen sections and a one-step nucleic acid amplification (OSNA) assay of the remaining whole node in patients with invasive breast cancer. In this article, we compared the intraoperative diagnostic ability of CK-IHC assay, the OSNA assay, and in combination.ResultsBetween August 2009 and May 2017, 1,103 SLNs from 499 consecutive clinically node-negative invasive breast cancers were intraoperatively evaluated for SLN metastases using an OSNA and CK-IHC assay. The detection rates of SLN metastases by the OSNA and CK-IHC assays and in combination were 11.8, 12.1, and 14.5%, respectively. The concordance rate between the intraoperative SLN findings of the OSNA and CK-IHC assays was 94.9% (95% confidence interval 93.6–96.2%). The false negative rate for the OSNA assay was 3.1% (30/973), including 3 (0.3%) macrometastases and 27 (2.8%) micrometastases, and for the CK-IHC assay was 2.7% (26/969), including 1 (0.1%) OSNA ++ and 25 (2.6%) OSNA +.ConclusionsThe CK-IHC assay and the OSNA assay have compatible diagnostic abilities in intraoperative evaluations for SLN metastases. The low incidence of false negative results with limited disease burden suggests that both assays can be reliable techniques for intraoperative diagnoses of SLN metastases in breast cancer patients.

FDG PET/CT and N0 mediastinal nodal status in early stage non-small cell lung cancer: A single institution retrospective experience.

11570 Background: The increasing use of CT and now low-dose screening CT scans for at-risk patients have led to increasing detection of lung cancer at early stages. FDG PET/CT is used as an adjunct to conventional imaging to assess loco-regional lymph node spread. However, there is a potential for false-negative results, especially in smaller lesions or early nodal involvement. The main objective of this study was to study the value of PET/CT scan to evaluate for true negative mediastinal nodes in patients with early stage NSCLC. Accurate determination of N0 status can have a significant impact on the cost-effectiveness and timely management of early stage NSCLC. Methods: Of a total of 404 patients with NSCLC managed at our facility between 2008 to 2015, 29 adult patients whose PET scan showed no or equivocal mediastinal nodal involvement and subsequently underwent surgical exploration of mediastinal lymph nodes were included in the study. Data variables that were collected included the cancer site, date of PET, node status on PET, type and date of surgery, cancer histology, and the tissue diagnosis of the sampled nodes. SAS software was used for the analysis of the data. Results: Of the 29 patients with N0 or equivocal nodes on FDG PET/CT, 7 (24.13%) had evidence of malignancy on biopsy of the surgically resected lymph nodes. No statistically significant differences were noted between the site of the neoplastic lesion, cancer histology, duration between the date of PET and the date of surgery in the true negative (TN) and false negative (FN) groups. The recurrence rate was higher in the FN group 60 % (3/5) compared to 21 % (4/19) in the TN group who had follow up for atleast 2 years. Conclusions: Our findings suggest incidence of false negative results of FDG PET/CT for evaluation of N0 nodes in early stage NSCLC is 24.13%. This is comparatively higher than false negatives rates with mediastinoscopy (5-10%) reported in other studies. Although our sample size is small, if confirmed, such a relatively high incidence of false negative results on FDG PET/CT for N0 disease supports the current recommendations for exploratory mediastinoscopy and/or surgery for definitive staging in early stage NSCLC.

Retrospective assessment of interobserver agreement and accuracy in classifications and measurements in subsolid nodules with solid components less than 8mm: which window setting is better?

To compare interobserver agreements among multiple readers and accuracy for the assessment of solid components in subsolid nodules between the lung and mediastinal window settings. Seventy-seven surgically resected nodules with solid components smaller than 8mm were included in this study. In both lung and mediastinal windows, five readers independently assessed the presence and size of solid component. Bootstrapping was used to compare the interobserver agreement between the two window settings. Imaging-pathology correlation was performed to evaluate the accuracy. There were no significant differences in the interobserver agreements between the two windows for both identification (lung windows, k = 0.51; mediastinal windows, k = 0.57) and measurements (lung windows, ICC = 0.70; mediastinal windows, ICC = 0.69) of solid components. The incidence of false negative results for the presence of invasive components and the median absolute difference between the solid component size and the invasive component size were significantly higher on mediastinal windows than on lung windows (P < 0.001 and P < 0.001, respectively). The lung window setting had a comparable reproducibility but a higher accuracy than the mediastinal window setting for nodule classifications and solid component measurements in subsolid nodules. • Reproducibility was similar between the two windows in nodule classifications. • Reproducibility was similar between the two windows in solid component measurements. • Accuracy for solid component assessment was higher on lung windows.

P96 – 3019: Hyperactivity, delayed speech, and coarse facies – Comes to mind Sanfilippo syndrome?

Mucopolysaccharidosis-IIIA or Sanfilippo-A syndrome is caused by deficiency of lysosomal a-heparan N-sulfatase that leads to accumulation of heparan-sulphate and degeneration of central nervous system with progressive dementia, hyperactivity, and aggressive behavior. Unlike other mucopolysaccharide disorders, the patients have little somatic features or skeletal changes and a high incidence of false-negative results on the urinary screening tests and so it remains underdiagnosed as a cause of developmental delay both in children and adults. We describe here a boy who presented with developmental delay, hyperactivity and behavioral problems. The attention of pediatricians should be drawn to hyperactivity, delayed language and developmental delay as possible initial presentations of mucopolysaccharidosis in order to avoid needless diagnostic and treatment procedures.

Diagnostic Accuracy of Routine Antenatal Determination of Fetal RHD Status Across Gestation

The RhD (RH1) antigen of the rhesus system is the most commonly implicated antigen for hemolytic disease of the fetus. Postnatal prophylaxis with anti-RhD immunoglobulin in RhD− women with an RhD+ child has been shown to reduce the risk of becoming alloimmunized. Subsequent introduction of routine antenatal prophylaxis with anti-RhD immunoglobulin in the third trimester for all RhD− women is now standard in many countries. Cell-free fetal DNA in maternal plasma can be tested for the presence or absence of the RHD gene, essentially screening for fetal Rh status. This prospective, multicenter cohort study was performed to determine the diagnostic accuracy of RHD genotyping in RhD− parturients and the optimal gestation for implementation into practice. From 2009 to 2012, consenting parturients had blood samples obtained at their initial appointment, at Down syndrome screening (11–21 weeks’ gestation), and at routine anomaly scanning (18–23 weeks’ gestation). At the third trimester visit (∼28 weeks), women were given the results of molecular testing, and an additional blood sample was obtained to confirm fetal RHD status. When this testing confirmed that the fetus was RHD−, women were allowed to opt out of receiving anti-RhD immunoglobulin. All women predicted to be carrying an RhD+ baby, or if the genotyping result was inconclusive, were offered anti-RhD immunoglobulin. All women who had a sensitizing event at less than 28 weeks were also offered anti-RhD immunoglobulin. RhD typing on cord blood samples was performed using routine serologic methods. Genotyping results were interpreted as RHD+, RHD−, or inconclusive. The final analysis included 2288 women and 4913 fetal genotype results with 4 analyses or less per parturient. Genotyping results were inconclusive for 393 samples (8.0%; 95% confidence interval, 7.3%–8.8%). Based on cord blood analyses, 2023 samples were from RhD− babies, of which 18 had been falsely predicted antenatally to be genotypically RHD+, and 85 were inconclusive; 2890 were RhD+, of which 308 were inconclusive on fetal RHD genotyping, and 19 were falsely predicted to be genotypically RHD−. The odds of correctly identifying RHD+ and RHD− fetuses increased significantly with gestational age, with low levels of false-negative results after 11 weeks’ gestation. At less than 11, 11 to 13, 14 to 17, 18 to 23, and more than 23 weeks, the sensitivities for detecting fetal RHD positivity were 96.85% (94.95%–98.05%), 99.83% (99.06%–99.97%), 99.67% (98.17%–99.94%), 99.82% (98.96%–99.97%), and 100% (99.59%–100%). At less than 11 weeks, 16 (1.9%) of 865 babies tested were falsely predicted to be RHD−. Massive throughput fetal RHD genotyping can be performed as soon as possible at 11 weeks or more. After 11 weeks, the incidence of false-negative results was considerably lower and did not decrease between 11 and 24 weeks, in agreement with evidence that concentrations of cell-free fetal DNA increase only minimally at 10 to 20 weeks’ gestation. The small number of false RHD− results after 11 weeks would lead to a small increase in the risk of alloimmunization. The tradeoffs between treating fewer women with antepartum immunoglobulin versus a few women becoming alloimmunized need to be considered carefully.

English

Oligonucleotide array hybridisation and multiplex polymerase chain reaction (m-PCR) can be used to screen and detect multiple foodborne pathogens. In our study, m-PCR and oligonucleotide array assays for the specific detection of the dominant foodborne bacterial pathogens, including&nbsp;Escherichia coli,&nbsp;Listeria monocytogenes,&nbsp;Salmonella&nbsp;spp., andShigella&nbsp;spp., in chicken meat were developed. The combination of m-PCR and an oligonucleotide array targeting the 16S rRNA,&nbsp;uspA,&nbsp;prfA,&nbsp;fimY, and&nbsp;ipaH&nbsp;genes displayed a high&nbsp;discriminatory power among the aforementioned genera and species with low or no incidence of false negative results. Our combined methods could detect all 4 target bacteria at amounts as low as 1 ng of each from mixed genomic DNA extracted from pure cultures, which&nbsp;is equivalent to 104-106&nbsp;CFU/ml. After enrichment steps for the target bacteria,&nbsp;E. coli,&nbsp;L. monocytogenes, and&nbsp;Salmonella&nbsp;sp. could be detected simultaneously from fresh chicken samples. Combining the two methods could enhance accuracy and sensitivity for foodborne pathogen detection and identification. The problems of cross-reactivities from non-target bacteria isolated from an enrichment culture and the difficulties in result interpretation by m-PCR could be solved using our oligonucleotide array hybridisation method. &nbsp; Key words:&nbsp;Oligonucleotide array, multiplex PCR, foodborne pathogens, target bacteria.

Hyperactivity, Unexplained Speech Delay, and Coarse Facies—Is It Sanfilippo Syndrome?

Mucopolysaccharidosis-IIIB or Sanfilippo-B syndrome is caused by deficiency of lysosomal α-N-acetylglucosaminidase that leads to accumulation of heparan-sulphate and degeneration of central nervous system with progressive dementia, hyperactivity, and aggressive behavior. Mucopolysaccharidosis-III remains underdiagnosed as a cause of developmental delay and hyperactivity both in adults and children because in contrast to other mucopolysaccharidoses, they have little somatic disease, coarse facial features, hepatosplenomegaly or skeletal changes, and a high incidence of false-negative results on the urinary screening tests. We describe here a girl with the classic phenotype of mucopolysaccharidosis-IIIB to alert pediatricians to the possibility of this disorder in children with unexplained speech delay and hyperactivity and prevent unnecessary investigations.

Role of endoscopic ultrasonography in the evaluation of extrahepatic cholangiocarcinoma.

Cholangiocarcinoma is a malignancy that arises from biliary epithelium and is associated with a poor prognosis. Accurate preopera-tive diagnosis and staging of cholangiocarcinoma continues to remain difficult. Endoscopic retrograde cholangiopancreatography (ERCP) is the most commonly performed procedure for cholangiocarcinoma and can provide a tissue diagnosis through brush cytology of the bile duct. However, the sensitivity of biliary brush cytology to diagnose cholangiocarcinoma may be as low as 30%. Endoscopic ultrasound (EUS) is a diagnostic modality which may overcome the limitations of other imaging and biopsy techniques in this setting. EUS can complement the role of ERCP and provide a tissue diagnosis through fine needle aspiration (FNA) and staging through ultrasound imaging. There is currently a paucity of data about the exact role of EUS for the diagnosis of cholan-giocarcinoma in patients with indeterminate extrahepatic biliary strictures. Although multiple studies have shown that EUS is more accurate than ERCP and radiologic imaging for identifying a biliary mass and diagnosing cholangiocarcinoma, the sensitivities are variable. More importantly, the incidence of false negative results is not negligible, though the specificity is close to 100%. There is also controversy regarding the role of EUS-FNA, since even though this may increase diagnosis, it can also lead to tumor seeding.

Comparison of three diagnostic methods to identify subclinical endometritis in mares

The objective of this study was to compare the accuracy of a uterine swab (US), a cytological brush (CB) and an endometrial biopsy (EB) to detect subclinical endometritis in mares. Cytological and bacteriological results of all three techniques were related to histological occurrence of polymorphonuclear neutrophils (PMNs) in the stratum compactum, commonly known as ‘best standard'; to diagnose endometritis.Samples were taken from 55 mares of different breeds without clinical signs of endometritis. Samples for US, CB and EB were collected, smeared on a microscopic slide and cultured for bacterial growth. Endometrial biopsy samples were additionally stored in 4% formaldehyde for histological analysis. Bacteriological cultures and cytological samples of all techniques were classified as negative (no uterine pathogens in monoculture; < 2% PMNs) or positive (uterine pathogens in > 90% of the grown colonies; > 2% PMNs) for endometritis. Uterine pathogens were diagnosed in 20.0% of the mares. Isolation of pathogens was not associated with positive cytological findings (r = −0.23; P = 0.87). None of the six mares with an Escherichia coli infection (10.9%) showed a positive cytological result. In contrast, two of five mares infected with Streptococcus zooepidemicus had a positive cytological result.Histologically, the presence of PMNs in the stratum compactum was regarded as positive for endometritis when the mare was in diestrus at time of sampling. Compared to the ‘best standard', sensitivity for cytology of CB, US and EB was 0.17, 0.00 and 0.25, respectively. Specificity for cytology of CB, US and EB was 0.83, 0.93 and 0.85, respectively. Sensitivity of uterine culture was 0.25, 0.33 and 0.25 for CB, US and EB, respectively. Specificity for culture of CB, US and EB was 0.80, 0.83 and 0.95, respectively. In conclusion, cytological or bacteriological examinations alone provide a high incidence of false negative results. Sensitivity of cytology combined with bacteriology of CB was 0.42. A combination of a bacteriological and a cytological examination of a CB sample improved the diagnostic performance in subfertile mares. Based on these results, we can recommend the CB to improve the diagnosis of subclinical endometritis in the mare compared to the US alone as currently used routine method.

Abstract P1-01-19: Comparison of Ultrasound-Guided Fine Needles Aspiration Cytology and Ultrasound Guided Core Biopsy in Pre-Operative Axillary Staging for Early Breast Cancer

Abstract Introduction: Pre-operative axillary staging is now widely accepted as a prerequisite in surgical management of the axilla for patients newly diagnosed with early breast cancer. For those patients having breast tumour excision who are found to have nodal involvement, axillary clearance can be performed at the same time without prior sentinel node biopsy. Ultrasound (US) alone has low sensitivity, but can be used to direct needle biopsy. We assessed and compared the sensitivity and specificity of US-guided core biopsies (USCB) and US-guided fine needle cytology (USFNAC) used in our unit. Patients and methods: A retrospective and prospective data collection was performed between November 2007 and May 2010 on all newly diagnosed breast cancer patients in our unit since the introduction of routine pre-operative axillary US. Patients whose nodes looked benign or normal on US were offered sentinel node biopsy (SNB). Patients found to have suspicious nodes were offered USFNAC or USCB, according to the individual preference of the radiologists. Patients with positive cytology or histology underwent axillary node clearances (ANC), those with benign cytology or histology were offered SNB. The final histology results were reviewed and correlated to their pre-operative histology or cytology. Results: Of 559 Axillary ultrasound scans performed in our department between November 2007 and May 2010, 229 patients had pre-operative US scans of the axilla for newly diagnosed, clinically node-negative breast cancer. Of these 46 had USFNAC, 44 had USCB and 139 had normal/benign US. The USFNAC and USCB groups had similar proportions of positive results on postoperative histology, namely 70% and 79% respectively, allowing direct comparisons to be made. Of the 46 USFNAC patients, 17 (37%) had positive cytology (all confirmed by axillary clearance final histology). The 29 USFNAC patients with negative cytology had 15 (52%) with positive histology on sentinel node biopsy. The sensitivity of USFNAC was 53% and the specificity 100%. Of the 44 USCB patients, 26 (59%) were positive (all confirmed by axillary clearance final histology). Of the 18 USCB-negative patients, 7 (39%) were found to be positive on axillary clearance. The sensitivity of USCB was 79% and the specificity 100%. Of the 139 patients with normal US, 42 (30%) were found to be positive on sentinel node biopsies. For US alone, sensitivity was 61% and specificity was 80%. Conclusion: US staging of the axilla is superior to clinical staging. However, there is still a high incidence of false negative results, making US a crude way of assessing the axilla and confirming the necessity for sentinel node biopsy in US-negative axillae. For patients with axillae that are indeterminate on US, our data supports routine use of ultrasound core biopsy (USCB) over Ultrasound fine needle aspiration cytology (USFNAC) for preoperative staging of the axilla, where technically feasible. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-19.

A Strategy to Avoid Missed Cases in a Brazilian Neonatal TSH Screening Program for Congenital Hypothyroidism

There have been reports of patients with primary hypothyroidism not identified by TSH measurement due to a presumably delayed rise in serum TSH. However, there are no data on the incidence of false negative results in neonatal screening programs employing primary TSH assay for diagnosis. To investigate the incidence of false negative results in a neonatal screening program using the primary TSH approach and evaluate a strategy to avoid misdiagnosis. 190 newborns, with initial TSH > 15.0 IU/l and < 20.0 IU/l (screening cutoff). These infants were submitted to a second TSH measurement around 30 days after the first screening. Thirty days after the first screening, four of the 190 infants (2.1%) remained with TSH levels around the cut-off screening level or higher. Of these four patients, three had an absence of thyroid gland on ultrasonography, with a final diagnosis of dysgenesis. The fourth patient had a normal shaped gland in its usual location by ultrasonography, with an outcome of transitory congenital hypothyroidism. The incidence of missed congenital hypothyroidism diagnoses in this neonatal screening program based on the TSH approach was low and acceptable. Nevertheless, with the proposed strategy, the risk of false negative results can be reduced without significant impact on the overall cost of the screening program.

False Negative CAH Screening Test More Likely in Girls

Endocrinology| April 01 2006 False Negative CAH Screening Test More Likely in Girls AAP Grand Rounds (2006) 15 (4): 47–48. https://doi.org/10.1542/gr.15-4-47-a Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation False Negative CAH Screening Test More Likely in Girls. AAP Grand Rounds April 2006; 15 (4): 47–48. https://doi.org/10.1542/gr.15-4-47-a Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search toolbar search search input Search input auto suggest filter your search All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: false-negative results Source: Varness TS, Allen DB, Hoffman GL. Newborn screening for congenital adrenal hyperplasia has reduced sensitivity in girls. J Pediatr. 2005;147:493–498. Researchers from the University of Wisconsin Children’s Hospital and the Wisconsin Newborn Screening Laboratory, Madison, analyzed the results of Wisconsin’s newborn screening for congenital adrenal hyperplasia (21- OH-D-CAH) from January 1, 2000-June 30, 2003 to determine the incidence of false negative results and detect possible differences in 17-hydroxyprogesterone (17-OHP) levels between male and female infants. During this period 119,842 male and 114,951 female infants were screened by the state program. The authors found 8 infants with false negative results. The overall sensitivity of CAH screening was 73%; for male infants sensitivity was 83%, for female infants 60%. All 8 infants with false negative results were full term and weighed more than 2200 g at birth. Their 17-OHP levels ranged from 8–55 ng/mL. Only 3 had levels >45 ng/mL, which is approximately 3 standard deviations above the mean. The comprehensive CAH panel was done to confirm the diagnosis of CAH for each patient. Seven of the 8 infants with false negative results were female. Of these, 5 were referred to an endocrinology clinic for evaluation of a genital abnormity and 2 were identified serendipitously when a newborn screen was repeated for reasons other than concern about CAH. The male was evaluated at age 54 months for premature adrenarche. Of the 7 female infants, 6 had an unidentifiable genital abnormality or genital masculinization. Four had biochemical evidence of salt-wasting; however, none of these infants died or had salt-wasting crisis. None of the patients were assigned the wrong sex. Five infants were identified by 3 months of age and the other 3 identified at >12 months old (ages ranged from birth to 54 months). The authors compared 17-OHP levels in male and female infants; levels in males were significantly higher than in females (mean values 17.5 ng/mL and 1.4 ng/mL, respectively; P<.001) The authors assessed whether lowering the threshold for a positive screen in girl infants might be an effective strategy. However, in the model proposed, only 3 of the 7 females who were missed with the current cut-offs would have been detected, and the rate of false positive tests would increase by 60%. Given that the primary goals of newborn screening for CAH are prevention of salt-wasting crises, mortality, and sex misassignment, the authors conclude that the current method of screening is satisfactory. However, health professionals should realize that newborn screening for 21-OH-D-CAH does not identify all affected infants. Dr. Varma has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of a commercial product/device. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device. In any newborn screening program there is the possibility of false negative results. False negative CAH screens have been reported in other countries.1,2 In a series from Sweden, there were 4 girls and 3 boys... You do not currently have access to this content.

A PCR-based method for the detection of genetically modified potatoes by the gene ac2 from Amaranthus caudatus

Genetically modified organisms have become a part of our everyday life. New modifications arise every year. The most of papers is focused on publication of detection protocols for genetically modified corn, soyabean, rape, or cotton. Minor modification, such as in potatoes attracts little attention. This work is based on developing an easy and cheap PCR method for the detection of an antimicrobial peptide from amaranthus which was used for transformation of potatoes. The base of the method is duplex PCR which enables identification of both potato and amaranthus specific genes in one tube. The method is enhanced by using positive plasmid controls which are able to reveal presence of inhibitors, reduce the incidence of false negative results, and wrong interpretation during analysis of routine samples.

Newborn Screening by Tandem Mass Spectrometry

After completing this article, readers should be able to: 1. List examples of disorders for which tandem mass spectrometry (MS/MS) can screen. 2. Delineate potential difficulties with MS/MS newborn screening. Tandem mass spectrometry (MS/MS) technology has shown tremendous promise in newborn screening pilot programs worldwide with its capacity to measure numerous metabolites from a dried blood spot virtually simultaneously with an extremely rapid throughput per sample (approximately 2 min). The expansion of newborn screening programs by inclusion of an additional 15 to 30 metabolic disorders has the potential to decrease significantly the morbidity and mortality associated with inborn errors of metabolism and could offer the clinician critical diagnostic information when caring for an acutely ill neonate. Newborn screening for metabolic disorders began in 1962 in the United States, with the introduction of the Guthrie bacterial inhibition assay for phenylketonuria (PKU) in a Massachusetts voluntary program. Child health advocates, including the National Association for Retarded Citizens and the March of Dimes Birth Defects Foundation, developed model legislation and lobbied for passage of newborn screening laws at the state level. As a result of these efforts, newborn screening for PKU was legally mandated in most states in the early 1960s. The success of newborn screening for PKU led to development of tests for other conditions, including metabolic disorders (eg, galactosemia, maple syrup urine disease [MSUD], homocystinuria, and biotinidase deficiency), endocrinopathies (eg, congenital hypothyroidism and congenital adrenal hyperplasia), hemoglobinopathies (eg, sickle cell disease and thalassemias), and cystic fibrosis. Different states screen for a variable number of these disorders, with most screening for three to six conditions (Figure⇓ ). Such differences reflect state political and economic environments, technologic capabilities of public health departments, regional ethnic composition, and community expectations. All states screen for PKU and congenital hypothyroidism, and 48 states screen for galactosemia. Other inborn …

Accuracy and reliability of the self-inflating bulb to verify tracheal intubation in out-of-hospital cardiac arrest patients.

To determine the sensitivity and specificity of the self-inflating bulb (SIB) to verify tracheal intubation in out-of-hospital cardiac arrest patients. Sixty-five consecutive adult patients with out-of-hospital cardiac arrest were enrolled. Patients were provided chest compression and ventilation by either ba-valve-mask or the esophageal tracheal double-lumen airway by ambulance crews when they arrived at the authors' department. Immediately after intubation in the emergency department, the endotracheal tube position was tested by the SIB and end-tidal carbon dioxide (ETCO2) monitor using an infrared carbon dioxide analyzer. We observed the SIB reinflating for 10 s, and full reinflation within 4 s was defined as a positive result (tracheal intubation). Five esophageal intubations occurred, and the SIB correctly identified all esophageal intubations. Of the 65 tracheal intubations, the SIB correctly identified 47 tubes placed in the trachea (72.3%). Delayed but full reinflation occurred in one tracheal intubation during the 10-s observation period. Fifteen tracheal intubations had incomplete reinflation during the observation period, and two tracheal intubations did not achieve any reinflation. Thirty-nine tracheal intubations were identified by ETCO2 (60%). When the SIB test is combined with the ETCO2 detection, 59 tracheal intubations were identified with a 90.8% sensitivity. The authors found a high incidence of false-negative results of the SIB in out-of-hospital cardiac arrest patients. Because no single test for verifying endotracheal tube position is reliable, all available modalities should be tested and used in conjunction with proper clinical judgment to verify tracheal intubation in cases of out-of-hospital cardiac arrest.

Efficacy of the Self-Inflating Bulb in Differentiating Esophageal from Tracheal Intubation in the Parturient Undergoing Cesarean Section

We studied the efficacy of the self-inflating bulb (SIB) in differentiating tracheal from esophageal intubation in 40 parturients undergoing elective cesarean section under general anesthesia. After induction and muscle relaxation, the trachea was intubated under direct vision with cuffed tube. In 20 parturients, the esophagus was also intubated with an identical tube. Before ventilation was initiated, an independent anesthesiologist checked tube positions with the SIB using two techniques. In one technique (T1), the SIB was compressed before connection to the tube; in the other technique (T2), the SIB was first connected to the tube and then compressed. The speed of reinflation was graded as rapid, delayed, and none. Tracheal tube position was reassessed immediately before and after delivery. Before initiation of controlled ventilation, the incidence of false negative results was 47.5% with T1 and 27.5% with T2 but significantly decreased to 17.5% with T1 and 7.5% with T2 when retested before delivery. After delivery, no false negative results occurred. The incidence of false positive results immediately after induction was 30% with T1 and 35% with T2. The mechanism of false negative responses may be attributed to decreased functional residual capacity leading to reduced caliber of intrathoracic airways and terminal airway closure; whereas false positive responses may be related to an incompetent gastroesophageal junction. We conclude that the SIB is unreliable for differentiating tracheal from esophageal intubation in the parturient undergoing cesarean section. (Anesth Analg 1997;84:533-7)