Low NPV Research Articles

Risk assessment of lymph node metastasis before surgery in endometrial cancer: Do we need a clinical trial for low‐risk patients?

Due to advances of radiological imaging and tumor biomarkers, the extent of information provided by preoperative assessment is rapidly growing. The Korean Gynecologic Oncology Group (KGOG) recently proposed new preoperative criteria to identify patients at low risk for lymph node metastasis in endometrial cancer. In the multicenter study, serum carbohydrate antigen 125 levels and three magnetic resonance imaging parameters were found to be independent risk factors for nodal metastasis, and classified 53% of patients as part of a low-risk group. The false-negative predictive value (NPV) was 1.7%, and was 1.4% in the validation set. Furthermore, the KGOG low-risk criteria were validated in 319 Japanese patients with endometrial cancer. The criteria identified 181 of 319 patients as a low-risk group (51%), and three false-negative cases were found (1.9%). These results indicate that we are able to identify low-risk patients with a negligible NPV before surgery. In addition, the low false NPV implies that there is great difficulty in performing a randomized trial to determine the efficacy of routine lymphadenectomy in patients at low risk of lymph node metastasis. Based on these data, the challenges and possible solutions for developing a consensus on the optimized management of low-risk endometrial cancer will be discussed in this review.

Evaluation of Genotype MTBDRsl Assay to Detect Drug Resistance Associated with Fluoroquinolones, Aminoglycosides and Ethambutol on Clinical Sediments

BackgroundThe emergence of resistant tuberculosis (TB) is a major setback to the global control of the disease as the treatment of such resistance is complex and expensive. Use of direct detection of mutations by molecular methods could facilitate rapid diagnosis of resistance to offset diagnostic delays. We evaluated the performance of the Genotype MTBDRsl (Hain Life Sciences) for the detection of second line resistant TB directly from stored smear positive sputum sediments.Methodology/Principal FindingsThe assay showed a diverse range of sensitivity and specificity, 91.26% [95% CI, 84–96] and 95.5% [95% CI, 87–99] for FQ (PPV ∼97% & NPV ∼ 87.67%), 56.19% [95%CI, 46–66] and 81% [95%CI, 66–91] for EMB (PPV ∼ 88.06% & NPV ∼ 43.21%) and 100% for SLD. Diagnostic accuracy for FQ, SLD and EMB was 94%, 100% and 63.51%, respectively. 1.17% (2/170) were heteroresistance strains, where the heteroresistance was linked to rrs gene. A varying rate of validity was observed 100% (170/170) for FQ, 94.11% (160/170) for EMB, 88.23% (150/170) for SLD.Conclusions/SignificanceGenotype MTBDRsl is simple, rapid, economical assay that can be used to detect commonly known resistance associated with Fluoroquinolone, second line injectable drugs and ethambutol. The assay detects the targeted resistance in less time as compared to phenotypic DST. But due to low NPV to FQ (88%) and EMB (43.21%), the assay results must be interpreted in coordination with the phenotypic DST.

Outcomes and Native Renal Recovery Following Simultaneous Liver–Kidney Transplantation

With the increase in patients having impaired renal function at liver transplant due to MELD, accurate predictors of posttransplant native renal recovery are needed to select candidates for simultaneous liver-kidney transplantation (SLK). Current UNOS guidelines rely on specific clinical criteria for SLK allocation. To examine these guidelines and other variables predicting nonrecovery, we analyzed 155 SLK recipients, focusing on a subset (n = 78) that had post-SLK native GFR (nGFR) determined by radionuclide renal scans. The 77 patients not having renal scans received a higher number of extended criteria donor organs and had worse posttransplant survival. Of the 78 renal scan patients, 31 met and 47 did not meet pre-SLK UNOS criteria. The UNOS criteria were more predictive than our institutional criteria for all nGFR recovery thresholds (20-40 mL/min), although at the most conservative cut-off (nGFR ≤ 20) it had low sensitivity (55.3%), specificity (75%), PPV (67.6%) and NPV (63.8%) for predicting post-SLK nonrecovery. On multivariate analysis, the only predictor of native renal nonrecovery (nGFR ≤ 20) was abnormal pre-SLK renal imaging (OR 3.85, CI 1.22-12.5). Our data support the need to refine SLK selection utilizing more definitive biomarkers and predictors of native renal recovery than current clinical criteria.

The efficacy of axillary ultrasound in the detection of nodal metastasis in breast cancer.

e21137 Background: Recent reports indicate a lack of survival benefit for axillary node dissection (ALND) versus sentinel lymph node biopsy in early breast cancer. To study this further we assessed the accuracy and effectiveness of ultrasound in detecting axillary nodal involvement in breast cancer patients, aimed at refining and evaluating our current clinical pathways as newly diagnosed invasive breast cancer patients routinely undergo pre-surgical axillary ultrasound. Methods: Ultrasound data were collected from consecutive breast cancer cases over 3 years. Images were reviewed by experienced radiologists and made the following assessments on size, morphology, fatty hilum and cortical thickness of the ipsilateral axillary nodes. The findings were correlated with histology outcomes following ALND. Results: 260 cases were included in the analysis, 113 (43.5%) had evidence of metastatic nodal involvement at final histology. Of these, 59/113 (52.2%) reported positive findings on ultrasonography. The overall positive predictive value of ultrasound for detecting metastatic nodal involvement measured 0.70. The negative predictive value was 0.61. The sensitivity was 52%, specificity measured 78% and the accuracy was 65%. The ultrasound morphological lymph node features with the greatest correlation with malignancy were absence of a fatty hilum (p=0.003) and increased cortical thickness (p=0.03). Cases with a metastatic nodal burden density of a least 20% were more likely to report an abnormal axillary ultrasound. (p=0.009). Conclusions: Axillary ultrasound has a low NPV and negative sonographic results do not exclude axillary node metastases with sufficient sensitivity, to justify its routine clinical use. Clinical pathways need to consider an evidence-based approach, focusing on the criteria by which we select breast cancer patients for axillary nodal dissection.

P2-08-02: Magnetic Resonance Imaging as a Predictor of Pathologic Response in Patients Treated with Neoadjuvant Systemic Treatment for Operable Breast Cancer (TBCRC 017).

Abstract Background: Increased pathologic complete response (pCR) rates observed with neoadjuvant chemotherapy for invasive breast cancer has prompted interest in whether patients with pCR can be identified preoperatively and potentially spared the morbidity of surgery. This multicenter retrospective study was performed to determine the accuracy of preoperative MRI in predicting pCR in the breast and whether MRI performance differs by molecular subtype, histology, and treatment regimen. Methods: 770 women from 8 institutions were retrospectively identified as having received neoadjuvant systemic therapy with MRI obtained at baseline and after completion of systemic treatment. Tumor phenotypes were defined on the basis of estrogen and progesterone receptor (ER/PR or HR) and HER2 receptor status. Univariate and multivariate analyses of factors influencing radiographic complete response (rCR) and pCR were recorded, with rCR defined as resolution of any abnormal enhancement, mass, or distortion on MRI, and pCR defined as resolution of both invasive disease and DCIS. Results: rCR and pCR for the total group were 182/746 (24%) and 179/746 (24%), respectively, with the highest rate of pCR seen among the triple-negative (TN; 57/155; 37%) and HR-/HER2+ (38/101; 38%) subtypes. Covariates significantly associated with rCR included T stage (p=0.0002), tumor grade (p=0.005), IHC phenotype (p=0.005), and chemotherapy regimen (p<0.0001). On multivariate analysis, only tumor phenotype was independently associated with likelihood of rCR, with both TN (OR = 2.00, 95% CI 1.20−3.33) and HR-HER2+ (OR=2.30, 95% CI 1.09–4.83) more likely to achieve rCR than HR+HER- (reference group). Overall accuracy of MRI for prediction of pCR was 74%. Sensitivity, NPV, PPV, and accuracy differed significantly among tumor subtypes, with the greatest NPV in the HR-/HER2+ and TN subtypes (table1). Among patients with rCR, ER- status (OR=6.4, 95% CI 1.1 to 35.6), PR- status (OR=3.8, 95% CI 1.2 to 11.4), and tumor grade of 3 vs 1 or 2 (OR=2.49, 95% CI 1.22−5.07) were independently associated with likelihood of pCR. Discussion: MRI performance for predicting pCR in patients with invasive breast cancer receiving neoadjuvant systemic therapy differed significantly among breast cancer subtypes; however this difference is likely due to subtype differences in frequency of pCR and not to intrinsically better or worse MRI detection. The relatively low NPV of MRI following neoadjuvant systemic therapy does not support using MRI rCR alone to accurately identify those patients that can safely avoid surgery. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-08-02.

704 PERCUTANEOUS RENAL MASS BIOPSY: IF THEY'RE POSITIVE, THEY'RE POSITIVE, BUT IF THEY'RE NEGATIVE, BE CAREFUL! A CORRELATION BETWEEN RENAL BIOPSY AND SURGICAL PATHOLOGY

You have accessJournal of UrologyKidney Cancer: Evaluation and Staging1 Apr 2011704 PERCUTANEOUS RENAL MASS BIOPSY: IF THEY'RE POSITIVE, THEY'RE POSITIVE, BUT IF THEY'RE NEGATIVE, BE CAREFUL! A CORRELATION BETWEEN RENAL BIOPSY AND SURGICAL PATHOLOGY Sameer M. Deshmukh, Luiz Sequeira, Francis McGovern, Douglas Dahl, Aria Olumi, Brian Eisner, W. Scott McDougal, Peter Mueller, Anthony Samir, and Adam S Feldman Sameer M. DeshmukhSameer M. Deshmukh Boston, MA More articles by this author , Luiz SequeiraLuiz Sequeira Boston, MA More articles by this author , Francis McGovernFrancis McGovern Boston, MA More articles by this author , Douglas DahlDouglas Dahl Boston, MA More articles by this author , Aria OlumiAria Olumi Boston, MA More articles by this author , Brian EisnerBrian Eisner Boston, MA More articles by this author , W. Scott McDougalW. Scott McDougal Boston, MA More articles by this author , Peter MuellerPeter Mueller Boston, MA More articles by this author , Anthony SamirAnthony Samir Boston, MA More articles by this author , and Adam S FeldmanAdam S Feldman Boston, MA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.1671AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Percutaneous biopsy is an emerging modality in the study of small renal masses. We correlated biopsy pathology results with surgical pathology specimens to investigate the concordance of the pathologic diagnoses. METHODS Under IRB approval, we performed a retrospective review of a database containing 899 patients who had undergone percutaneous biopsy of renal masses at our institution from 1997-2010. Core biopsies were performed using 15–18 gauge cutting needles and fine needle aspirations (FNAs) were performed with 20–23 gauge Chiba needles. 247/899 (27%) patients underwent surgical extirpation of their renal masses. Biopsy and surgical pathologic data were compared. RESULTS 161/247 (65%) patients underwent radical nephrectomy and 86/247 (35%) underwent partial nephrectomy. Mean tumor size was 3.6cm (± 2.3). Median age was 59 years (range 26–88). There were 217 (88%) solid lesions and 30 (12%) cystic lesions. Median time to surgical intervention was 1.68 months (range 0.03–58.7 months). Of 203 percutaneous biopsies demonstrating renal cell carcinoma (RCC), 196 (97%) were RCC on final pathology. Histologic subtype was assessed in 159 biopsy specimens and was correct in 145/159 (91%). Subtype was not specified in 44/203 (22%). 34 lesions identified on biopsy as “benign” or “non-diagnostic” went to surgery because of imaging suspicion or size change; of these, 20 proved to be RCC. Although there is inherent selection bias in this surgical cohort, the sensitivity of renal biopsy for malignancy was 0.89 and the specificity was 0.69. The positive predictive value of biopsy was 0.98 while the negative predictive value was 0.31. Fuhrman grading was reported in 60 percutaneous biopsies. Grade was concordant in 47/60 (78%). CONCLUSIONS Percutaneous renal mass biopsy can accurately determine pathology in suspicious renal masses. However, the low NPV highlights the need for strict follow-up in patients with a non-malignant biopsy result. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e283 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sameer M. Deshmukh Boston, MA More articles by this author Luiz Sequeira Boston, MA More articles by this author Francis McGovern Boston, MA More articles by this author Douglas Dahl Boston, MA More articles by this author Aria Olumi Boston, MA More articles by this author Brian Eisner Boston, MA More articles by this author W. Scott McDougal Boston, MA More articles by this author Peter Mueller Boston, MA More articles by this author Anthony Samir Boston, MA More articles by this author Adam S Feldman Boston, MA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Understanding the Utility of Zero Coronary Calcium as a Prognostic Test

Coronary artery calcium (CAC) is nearly pathognomonic for the presence of coronary atherosclerosis, although not all coronary plaque is calcified.1,2 As such, cardiac CT scans for CAC are highly specific but less sensitive for the presence of some coronary atherosclerosis. In contrast, these tests are highly sensitive but less specific for detecting obstructive atherosclerotic coronary artery disease (CAD). A Bayesian approach is critical for discerning the value of new tests. When used in the intended population, a test with high sensitivity is excellent for ruling out disease (ie, highly sensitive tests produce a high negative predictive value [NPV] when negative). For this reason, there is interest in using “zero” CAC scores to predict excellent prognosis—and potentially conserve medical resources—in the large population of patients at intermediate midterm risk of developing clinical cardiovascular disease. The efficiency of any test relies on the frequency of disease in the population tested (the prior probability distribution). For example, take the d-dimer test for deep venous thrombosis and pulmonary embolism. If a d-dimer is checked in all outpatients, a low positive predictive value (PPV) will result given the low frequency of thrombosis in this scenario. If a d-dimer is tested exclusively in patients with acute dyspnea and a swollen lower extremity, there will be a low NPV given the high incidence of pulmonary embolism in such patients. Stated in mathematical terms, the likelihood of thrombosis (A) given a positive d-dimer (B) depends not only on the conditional probability of B given the presence or absence of A (the test characteristics), but also on the marginal probability of A independent of B (the prior probability distribution). This principle is summarized in probability theory by Bayes theorem (Figure 1). Knowingly or unknowingly, Bayes theorem underlies essentially all clinical decision making. …

Defining the True Sensitivity of Culture for the Diagnosis of Melioidosis Using Bayesian Latent Class Models

BackgroundCulture remains the diagnostic gold standard for many bacterial infections, and the method against which other tests are often evaluated. Specificity of culture is 100% if the pathogenic organism is not found in healthy subjects, but the sensitivity of culture is more difficult to determine and may be low. Here, we apply Bayesian latent class models (LCMs) to data from patients with a single Gram-negative bacterial infection and define the true sensitivity of culture together with the impact of misclassification by culture on the reported accuracy of alternative diagnostic tests.Methods/Principal FindingsData from published studies describing the application of five diagnostic tests (culture and four serological tests) to a patient cohort with suspected melioidosis were re-analysed using several Bayesian LCMs. Sensitivities, specificities, and positive and negative predictive values (PPVs and NPVs) were calculated. Of 320 patients with suspected melioidosis, 119 (37%) had culture confirmed melioidosis. Using the final model (Bayesian LCM with conditional dependence between serological tests), the sensitivity of culture was estimated to be 60.2%. Prediction accuracy of the final model was assessed using a classification tool to grade patients according to the likelihood of melioidosis, which indicated that an estimated disease prevalence of 61.6% was credible. Estimates of sensitivities, specificities, PPVs and NPVs of four serological tests were significantly different from previously published values in which culture was used as the gold standard.Conclusions/SignificanceCulture has low sensitivity and low NPV for the diagnosis of melioidosis and is an imperfect gold standard against which to evaluate alternative tests. Models should be used to support the evaluation of diagnostic tests with an imperfect gold standard. It is likely that the poor sensitivity/specificity of culture is not specific for melioidosis, but rather a generic problem for many bacterial and fungal infections.

Presumptive varicella vaccination is warranted in Greek adolescents lacking a history of disease or household exposure

Current practice favors serotesting adolescents with a negative history of chickenpox rather than offering presumptive vaccination. Recent epidemiologic data from Greece indicate that a high proportion of adolescents (21.5%) are susceptible to chickenpox. We assessed the reliability of negative varicella history in relation to type of exposure in 311 children and 283 adolescents. In children with social or unknown exposure to varicella, a negative history had a high negative predictive value (NPV = 73.5), supporting the clinical practice of presumptive vaccination. Conversely, children with a negative history and household exposure had a low NPV (13.8), suggesting that pre-vaccination serologic testing is warranted. In conclusion, based on our local epidemiologic data, presumptive varicella vaccination should be offered to all adolescents with the exception of the subgroup of adolescents with household exposure.

Up-regulation of proliferating cell nuclear antigen (PCNA) is closely associated with high-risk human papillomavirus (HPV) and progression of cervical intraepithelial neoplasia (CIN), but does not predict disease outcome in cervical cancer

Objective Proliferating cell nuclear antigen (PCNA) is essential for DNA replication of mammalian cells and their small DNA tumour viruses. The E7 oncoprotein of high-risk human papillomavirus (HPV) is known to activate PCNA, shown to be up-regulated in CIN and cervical cancer (CC), but still incompletely studied as an intermediate endpoint marker in this disease. Material and methods As part of our HPV-PathogenISS study, a series of 150 CCs and 152 CIN lesions were examined using immunohistochemical (IHC) staining for PCNA, and tested for HPV using PCR with three primer sets (MY09/11, GP5 +/GP6 +, SPF). Follow-up data were available from all SCC patients, and 67 of the CIN lesions had been monitored with serial PCR for HPV after cone treatment. Results Expression of PCNA increased in parallel with the grade of CIN, with major up-regulation upon transition to CIN3 (OR 21.77; 95%CI 6.59–71.94) ( p = 0.0001). Intense PCNA expression was 100% specific indicator of CIN, with 100% PPV, but suffers from low sensitivity (34.8%) and NPV (10.8%). PCNA expression was also significantly associated to HR-HPV with OR 3.02 (95%CI 1.71–5.34) ( p = 0.0001), and this association was not confounded by the histological grade (Mantel–Haenszel common OR = 2.03; 95%CI 1.06–3.89) ( p = 0.033). Expression of PCNA did not predict clearance/persistence of HR-HPV after treatment of CIN, and it was not a prognostic predictor in CC in univariate or in multivariate analysis. Conclusions Up-regulation of PCNA was closely associated with HR-HPV and progressive CIN, most feasibly explained by the abrogation of normal cell cycle control by the E7 ongogene, reverting the p21 Cip1-mediated inhibition of PCNA. However, the fact that PCNA is also expressed in normal squamous epithelium precludes the use of this marker as a potential screening tool for CC.

Sensitivity analysis in calculating the social value of carbon sequestered in British grown Sitka spruce

We describe a model that estimates the social benefits of carbon (C) sequestered in plantation Sitka spruce in Great Britain. Final net present values (NPV, base year=2003) resulting from plausible variations in model parameters are calculated. The discount rate, social value of C, timber yield, rate of gain into live wood, length of rotation, lifetime of products, amount of C displaced by products and the changes in C flux on afforested peat soils are the most influential model components. The study predicts that C fluxes in actively managed forests in second or subsequent rotations or planted on peat soils will tend to have low or (on average) negative NPV.

Upregulation of telomerase (hTERT) is related to the grade of cervical intraepithelial neoplasia, but is not an independent predictor of high-risk human papillomavirus, virus persistence, or disease outcome in cervical cancer

Telomerase activation and telomere maintenance are essential for cell immortalization and represent a rate-limiting step in cancer progression. The E6 oncoprotein of high-risk human papillomavirus (HPV) is known to activate telomerase, but its expression in CIN lesions and its prognostic value in cervical cancer (CC) are still incompletely understood. As part of our HPV-PathogenISS study, a series of 150 CCs and 152 CIN lesions were examined using immunohistochemical (IHC) staining for hTERT (telomerase reverse transcriptase), and tested for HPV using PCR with three primer sets (MY09/11, GP5(+)/GP6(+), SPF). Follow-up data were available from all SCC patients, and 67 CIN lesions had been monitored with serial PCR for HPV after cone treatment. Expression of hTERT was increased in parallel with the grade of CIN, with major up-regulation upon transition to CIN3 (OR 18.81; 95% CI 8.48-41.69; P = 0.0001). Positive hTERT expression was 90% specific indicator of CIN, with 98.7% PPV, but suffers from low sensitivity (57.5%) and NPV (14.3%). hTERT expression was also significantly associated to HR-HPV with OR 3.38 (95% CI 1.90-6.02; P = 0.0001), but this association was confounded by the histological grade (Mantel-Haenszel common OR = 1.83; 95% CI 0.92-3.79; P = 0.086). Expression of hTERT did not predict clearance/persistence of HR-HPV after treatment of CIN, and it was not a prognostic predictor in cervical cancer in univariate or multivariate survival analysis. It was concluded that up-regulation of hTERT was closely associated with HR-HPV, due to activation by the E6 oncoprotein. hTERT is a late marker of cervical carcinogenesis, significantly associated with progression to CIN3. Theoretically, a combination of hTERT assay (showing high SP and PPV) with another test showing high SE and high NPV (e.g. Hybrid Capture 2 for HPV), should provide an ideal screening tool capable of high-performance detection of CIN lesions.

Ecosystem structure along bioclimatic gradients in Hawai'i from imaging spectroscopy

The Hawaiian Islands contain more than two-thirds of the life zones delineated by Holdridge, L.R., 1947. Determination of world plant formations from simple climate data. Science, 105, 367–368, and is thus an ideal testing ground for remote sensing studies of ecosystem function and structure. We tested the generality of imaging spectroscopy with “tied” red-edge and shortwave-infrared (RE-SWIR2) spectral mixture modeling for automated analysis of the lateral distribution of plant tissues and bare substrate across diverse bioclimatic gradients in Hawai'i. Unique quantities of the fractional cover of photosynthetic and non-photosynthetic vegetation (PV, NPV) and bare substrate identified fundamental differences in ecosystem structure across life zones. There was a ∼20-fold increase in fractional PV cover with a 10-fold increase in mean annual precipitation (≤ 250–2000 mm year − 1 ). This rate of increase diminished from 2000 to 3000 mm year − 1 of rainfall, suggesting that photosynthetic canopy cover may be limited by water saturation at 3000 mm year − 1 . The amount of exposed surface senescent material (NPV) remained nearly constant at ∼50% in ecosystems with a mean annual precipitation < 1500 mm year − 1 . Thereafter, NPV steadily declined to a minimum of ∼20% at 3000 mm year − 1 of rainfall. Bare substrate fractions were highest (∼50%) at precipitation levels < 750 mm year − 1 , then declined to < 20% in the 750–1000 mm year − 1 zones. The combination of low bare substrate and high NPV cover in the 750–1000 mm year − 1 rainfall zones identified these areas as high fire risk. Remotely sensed fractional cover of PV + NPV was poorly correlated with canopy leaf area index (LAI), showing the uniqueness of the lateral structural measurement afforded by automated RE-SWIR2 spectroscopy approaches. The results indicate the accuracy, precision and applicability of imaging spectroscopy for ecological research across a wide range of bioclimatic conditions.

Asymmetric Information, Choice of Workout under Financial Distress, and Absolute Priority Violations

We study the reorganization of a financially distressed firm when public debt-holders are uninformed about future profitability of its projects. With large expected NPV of the continuation project, exchange offers restructure the public debt. Low NPV results in liquidation. For intermediate ranges of NPV, the bank refinances the short-term public debt. We show that the signaling requirements of exchange offers imply additional equity to the firm's shareholders in violation of the Absolute Priority Rule. Our analysis derives testable hypothesis relating the nature of workouts and the magnitude of APR violations to observables such as the short term public debt.

Frequency of heparin-induced thrombocytopenia in critical care patients.

The diagnosis of heparin-induced thrombocytopenia (HIT) in critically ill patients is complicated by lack of information on the frequency of HIT relative to thrombocytopenia from other causes. In addition, results from HIT diagnostic tests have not been clearly evaluated for clinical utility. In this prospective study, we estimated the frequency of HIT and the predictive performance of the heparin-platelet factor 4 enzyme-linked immunosorbent assay (heparin-PF4 ELISA) in 748 consecutive, heparin-treated patients in a combined intensive and coronary care unit. The criteria for diagnosis were as follows: two or more consecutive platelet counts below 150 x 10(3)/mm3 or a 33% or greater decrease in platelet count 5 or more days after beginning heparin, or any time after starting heparin for patients exposed to the agent within the previous 8 weeks; and a positive 14C-serotonin release assay (SRA), the reference standard. Specificity and predictive values for the heparin-PF4 ELISA were estimated in patients who met the clinical criteria for HIT. Of 748 patients, 267 were exposed to heparin for a sufficient length of time to be considered to be at risk for HIT. Forty of these patients (15.0%, 95% confidence interval [CI] 10.7%-19.3%) met the clinical criteria for HIT. Serum samples were available for 32 of these patients, one of whom tested positive by the SRA, yielding a HIT frequency of 0.39% (95% CI 0.01-2.1%). The specificity of the heparin-PF4 ELISA among thrombocytopenic patients with negative SRA results was 71%, and the positive (PPV) and negative (NPV) predictive values of this test were estimated to be 10% and 100%, respectively. The point estimate of the frequency of HIT in critically ill patients was less than 1% in this cohort. The low PPV and high NPV of the heparin-PF4 ELISA suggest that it can be used to exclude HIT as a cause of thrombocytopenia in this patient population.

Dobutamine stress echocardiography in the detection of coronary artery disease in a clinical practice setting

In this prospective study, patients referred for coronary angiography for detection of disease underwent dobutamine stress echocardiography to define its value in a clinical practice setting. Results: Of 219 patients studied, 170 (78%) had significant coronary artery disease. The overall sensitivity and specificity of dobutamine stress echocardiography for coronary artery disease were 82 and 65%, respectively. The sensitivity was 88% for detection of triple-vessel disease, 83% for double-vessel disease, and 74% for single-vessel disease. Positive and negative predictive values for coronary artery disease were 89 and 51%, respectively. Dobutamine stress echocardiography correctly identified only 72 of 138 patients with significant stenosis of the left anterior descending coronary artery. In 219 patients, 345 of 657 major epicardial vessels had significant disease. Dobutamine stress echocardiography could only correctly identify the vessel involved in 188. Triple-vessel disease was present in 65 patients. Dobutamine stress echocardiography correctly categorised 18% ( n=12) of these. The remainder were incorrectly classified as having double-vessel disease or single-vessel disease ( n=45), or no disease at all ( n=8). Conclusion: Dobutamine stress echocardiography performs well. However, lower specificity may lead to unwarranted referrals for coronary angiography, and the low NPV give false reassurance as to the absence of disease.

Role of pulmonary function in the detection of allograft dysfunction after heart-lung transplantation.

BACKGROUND: Lung function is altered by infection and rejection in patients who undergo heart-lung transplantation. The sensitivity, specificity, and positive/negative predictive values (PPV and NPV) of lung function for the...

Immunological Aspects of Skin Diseases

<h3>Abstract</h3> <h3>Background</h3> Bacterial meningitis is a dangerous infection that can kill children and adults alike. An estimated 1.2 million instances of bacterial meningitis are anticipated to occur globally each year, despite the discovery of polysaccharide and conjugate vaccines in recent years [1]. The study aimed to find out which bacteria isolates are linked to meningitis and to compare the culture method to the rT-PCR method. <h3>Method</h3> This study examined data on bacterial meningitis from the Ghana Health Service’s Public Health Division from 2015 to 2019. Patients’ information was collected from case-based forms held at the Tamale Public Health and Reference Laboratory. The data from the case-based forms was transcribed into a pre-designed Microsoft Excel template. For analysis, the data was cleaned and loaded into Minitab version 18. <h3>Results</h3> There were 2,446 CSM cases documented in all, 34.4 percent were confirmed. Males (52.7%) were more suspected than females (47.3%). Age group 15-44 were affected most (37.5%). The predominant pathogens were <i>Neisseria meningitidis</i> (W135) and <i>Streptococcus pneumoniae</i> (St.1) with NMX, St.14, St.19, and St. 12F/12A/12b as new emerging strains. Notwithstanding that, low NPV (72.6%), NLR (0.69), and sensitivity (31.8%) of culture method for detected pathogens of bacterial meningitis were found to produce a statistically significant false negatives compared to the gold standard (rT-PCR). <h3>Conclusion</h3> Emergence of new strains of bacterial meningitis and the false negative results chained out by the culture method is alarming.

Net protein values for the growing chicken from carcass analysis with special reference to animal protein sources

AbstractThe use of this laboratory's variation of the carcass N retention method was extended to a study of common protein sources (mostly animal protein) used in the laboratory or in commercial feeds for growing chickens. The following conclusions were made : Whole egg protein and egg albumen were the best protein sources tested, although the NPV results were considerably lower than those reported for growing rats. Crude casein was greatly improved by supplementation with arginine, glycine and methionine, but the NPV of the supplemented protein was still not as good as that of the isolated soya‐bean protein with added methionine. Zein and gelatin gave NPV results of approximately 20 even though the birds lost weight. Supplementing gelatin with essential amino‐acids to simulate isolated soya‐bean protein with added methionine, doubled the NPV but it was still much lower than the values for the latter. Menhaden fish meal approached the value obtained for the methionine‐supplemented isolated soya‐bean protein. Even a heat‐damaged sample was still superior to meat meal as a protein source. The very low NPV results for four samples of meat meal from different sources could be attributed to their high collagen content as calculated from hydroxyproline determination.