False-positive Results Research Articles

Biomarker-triggered, spatiotemporal controlled DNA nanodevice simultaneous assembly and disassembly.

Despite many advances in the use of DNA nanodevices as assembly or disassembly modules to build various complex structures, the simultaneous assembly and disassembly of DNA structures in living cells remains a challenge. In this study, we present a modular engineering approach for assembling and disassembling DNA nanodevices in response to endogenous biomarkers. As a result of pairwise prehybridization of original DNA strands, the DNA nanodevice is initially inert. In an effort to bind one of the paired strands and release its complement, nucleolin competes. Assembly of the DNA nanodevice is initiated when the released complement binds to it, and disassembly is initiated when APE1 shears the assembled binding site of the DNA nanodevice. Spatial-temporal logic control is achieved through our approach during the assembly and disassembly of DNA nanodevices. Furthermore, by means of this assembly and disassembly procedure, the sequential detection and imaging of two tumor markers can be achieved, thereby effectively reducing false-positive signal results and accelerating the detection time. This study emphasizes the simultaneous assembly and disassembly of DNA nanodevices controlled by biomarkers in a simple and versatile manner; it has the potential to expand the application scope of DNA nanotechnology and offers an idea for the implementation of precision medicine testing.

Клінічний випадок захворювання, підозрілого на хворобу Лайма, з незвичайними результатами серологічного обстеження

The article p examination: positive results of IgM and IgG antibodies to B. burgdorferi, obtained by the method of blot analysis (WB), and negative results of examination by the method of enzyme immunoassay (ELISA), which resents a case of a disease suspected of Lyme disease with unusual results of serological were made later in two other laboratories. The advantages of the two-stage diagnosis of Lyme disease with the sequential use of ELISA and WB and the possible consequences of the diagnosis of the disease using only one laboratory technique are considered. Attention is drawn to differences in the interpretation of WB results according to the criteria of the Center for Disease Control (CDC, USA) and manufacturers of alternative test systems. Factors that can contribute to false-positive examination results are considered: depending on the patient (the presence of concomitant rheumatic, infectious diseases) and on the erroneous interpretation of the results of laboratory tests (considering weakly positive bands as a positive result, the presence of several bands within one, neglecting a slight shift of the band in relation to its location in control, etc.). Attention is also drawn to the impacton the results of the study of the presence of «anamnestic» antibodies in a certain percentage of people living inareas endemic for Lyme disease. Based on the above theoretical propositions, a thorough analysis was carried out regarding the compliance of the clinical manifestations of the case of the disease considered in the article with the criteria of the early localized form of Lyme disease. On the basis of the criteria found in scientific publications, a clinical and epidemiological comparison of the patient’s data with the results of laboratory examination was carried out regarding their reliability. A conclusion is made regarding the need to rely on clinical data when diagnosing Lyme disease, and to consider laboratory examination results as additional confirmation of the diagnosis. It is emphasized that the high specificity (98%) of the laboratory examination is ensured only due to the two-stage research method with the sequential use of ELISA and WB. In case of questionable WB results, clinical and epidemiological data should be compared with the results of laboratory examination for their reliability. Keywords: Borrelia burgdorferi, diagnosis, IgM IgG immunoblot, Lyme disease, serology

Determination of 15 preservative allergens in cosmetics by gas chromatography-tandem mass spectrometry

Most preservatives are irritating and can easily induce skin sensitivities. Therefore, both domestic and international regulations impose clear restrictions on the use of preservatives in cosmetics. Herein, gas chromatography-tandem mass spectrometry (GC-MS/MS) was employed to simultaneously analyze the levels of 15 preservative allergens in cosmetics. Further, a precise identification approach based on a two-column retention index and mass spectrometry matching degree was developed. Cosmetic samples were extracted via acetonitrile vortex ultrasound extraction and then dehydrated with anhydrous MgSO4. The preservative allergens were separated on two columns, namely, DB-5MS and DB-WAX. Targets were identified using electron impact ionization (EI) source and the multiple reaction monitoring (MRM) mode and characterized using a retention index calibrated by a series of n-alkane standards. Following two tests, the LODs for the 15 preservative allergens on the DB-5MS column were in the range of 0.02-0.2 mg/kg, while those for 12 preservative allergens on the DB-WAX column were in the range of 0.01-20 mg/kg. The preservative allergens on the DB-5MS and DB-WAX columns demonstrated strong correlations, with all correlation coefficients exceeding 0.99. The recoveries for the 15 preservative allergens were in the range of 70.1%-129.8% at low, medium, and high levels, and the relative standard deviations (RSDs) were all below 15% (n=6) when using water, lotion, facial mask, and cream as the representative matrix. Next, 80 batches of genuine samples were tested using the established method. Isopropyl 4-hydroxybenzoate, a prohibited preservative, was detected in two sample batches using the DB-5MS and DB-WAX columns. Additionally, 11 and 10 restricted preservative allergens were identified on the DB-5MS and DB-WAX columns, respectively. The test results indicate that the double-column system approach offers excellent accuracy, effectively preventing false-positive and false-negative results, and can detect the 15 preservative allergens in cosmetics. The use of the retention index for the qualitative detection of these preservative allergens offers valuable options for non-targeted screening and meeting regulatory criteria.

An Overview of Peptides and Peptide Pools for Antigen-Specific Stimulation in T-Cell Assays.

The analysis of antigen-specific T-cell responses has become routine in many laboratories. Functional T-cell assays like enzyme-linked-immuno-spot (ELISPOT), which depend on antigen-specific stimulation, increasingly use peptides to represent the antigen of interest. Besides single peptides, mixtures of peptides (peptide pools) are very frequently applied. Such peptide pools may, for example, represent entire proteins (with overlapping peptides covering a protein sequence) or include noncontiguous peptides such as a collection of T-cell-stimulating peptides. The optimum specification of single peptides or peptide pools for T-cell stimulation assays will depend on the purpose of the test, the target T-cell population, the availability of sample, requirements regarding reproducibility, and, last but not least, the available budget, to mention only the most important factors. Because of the way peptides are produced, they will always contain certain amounts of impurities such as peptides with deletions or truncated peptides, and there may be additional by-products of peptide synthesis. Optimized synthesis protocols as well as purification help reduce impurities that might otherwise cause false-positive assay results. However, specific requirements with respect to purity will vary depending on the purpose of an assay. Finally, storage conditions significantly affect the shelf life of peptides, which is relevant especially for longitudinal studies. The present book chapter addresses all of these aspects in detail. It should provide the researcher with all necessary background knowledge for making the right decisions when it comes to choosing, using, and storing peptides for ELISPOT and other T-cell stimulation assays.

The Method of Everything vs. Experimenter Bias of Loophole-Free Bell Experiments.

Experimenter bias compromises the integrity and advancement of science, especially when awarded as such. For example, the 2022 Nobel Prize in Physics awarded for the loophole-free experiments that tested physicist John S. Bell's inequality theorem. These experiments employed the logic of conducting local experiments to obtain local evidence that contradicted local realistic theories of nature, thereby validating quantum mechanics as a fundamental non-local theory. However, there was one loophole that was wittingly not tested by the Nobel laureates. The notable exception was Bell's "super-deterministic" loophole, which was validated (2000) (2001) (2002) (2003) (2004) (2005) (2006) (2007) (2008) (2009) (2010) (2011) (2012) non-locally, thus compromising the subsequent Nobel Prize. More importantly, the discovery of two mutually exclusive and jointly exhaustive non-local hidden variables revealed why local scientific methods obtain false-positive and false-negative results. With knowledge of this fundamental omission, the inclusion of the non-local hidden variables in the local methods used in science can then advance it to be a complete study of nature.

Development of a disposable paper-based thin film solid-phase microextraction sampling kit to quantify ketone body.

Diabetes ketoacidosis (DKA) is a life-threatening complication and requires immediate medical attention in the case of diabetes subjects, especially in the case of type 1 diabetes mellitus. In the condition of DKA, the body produces an excess amount of ketone bodies after unregulated fat degradation, causing blood to become acidic and hampering the regular metabolic activities of the body. The current diagnostic technique for DKA condition is based on monitoring ketone bodies, especially β-hydroxybutyric acid, from human urine and blood samples. The detection of serum ketone bodies in pathology is sometimes limited due to false positive results and the lack of standardization for precise quantification of analytes. In this study, a paper-based patch operating on the thin film solid-phase microextraction (TF-SPME) principle was developed and it was coupled with gas chromatography-mass spectrometry for simple quantification of β-hydroxybutyric acid (BHB) ketone body from a phosphate-buffered saline matrix. To fabricate the paper-based TF-SPME patches, a regular A4 sheet paper sheet was utilized as the substrate and uniform coating by multiwalled carbon nanotubes (MWCNT), polydimethylsiloxane (PDMS) and divinyl benzene (DVB) compounds was performed with an automatic film applicator. The 70 μm paper-based coated sheet was trimmed into 4 cm × 1 cm dimension pieces to obtain multiple patches from a single sheet. Extraction of the BHB ketone body into the closed vials was performed by exploiting the individual DVB/PDMS and DVB/CNT/PDMS paper patches followed by desorption with acetonitrile before quantification by gas chromatography-mass spectrometry analysis. Our study showed that the BHB extraction efficiency of DVB/PDMS-coated patches was higher than that of DVB/CNT/PDMS. The outcome showed a good linearity (R 2 = 0.99) within the 500-20 000 ng mL-1 concentration range of BHB by paper-based DVB/PDMS patches. This study demonstrated the feasibility of utilizing simple, cost-effective paper-based disposable TF-SPME patches as a sampling kit for future screening of diabetes ketoacidosis without the need for prolonged traditional sample preparation in pathology.

Strategic Retesting to Reduce False Positive SARS-CoV-2 PCR Test Results.

Nucleic acid amplification testing is the gold standard for SARS-CoV-2 diagnostics, although it may produce a certain number of false positive results. There has not been much published about the characteristics of false positive results. In this study, based on retesting, specimens that initially tested positive for SARS-CoV-2 were classified as true or false positive groups to characterize the distribution of cycle threshold (CT) values for N1 and N2 targets and number of targets detected for each group. Specimens that were positive for N-gene on retesting and accompanied with S-gene were identified as true positives (true positive based on retesting, rTP), while specimens that retested negative were classified as false positives (false positive based on retesting, rFP). Of the specimens retested, 85/127 (66.9%) were rFP, 16/47 (34.0%) specimens with both N1 and N2 targets initially detected were rFP, and the CT values for each target was higher in rFP than in rTP. ROC curve analysis showed that optimal cutoff values of CT to differentiate between rTP and rFP were 34.8 for N1 and 33.0 for N2. With the optimal cutoff values of CT for each target, out of the 24 specimens that were positive for both N1 and N2 targets and classified as rTP, 23 (95.8%) were correctly identified as true positives. rFP specimens had a single N1 target in 52/61 (85.2%) and a single N2 target in 17/19 (89.5%). Notably, no true positive results were obtained from any specimens with only N2 target detected. These results suggest that retesting should be performed for positive results with a CT value greater than optimal cutoff value for each target or with a single N1 target amplified, considering the possibility of a false positive. This may provide guidance on indications to perform retesting to minimize the number of false positives.

Evaluation of pregnancy associated glycoproteins assays for on farm determination of pregnancy status in beef cattle.

Transrectal ultrasonography is known as the gold standard for pregnancy detection, but requires costly equipment and technical skills; therefore, access to an inexpensive and more user-friendly method with similar accuracy could benefit cattle producers. Detection of pregnancy-associated glycoproteins can accurately determine pregnancy in ruminants; however, usually requires specialized equipment for the assay. Thus, the objectives of these studies were to 1) validate the IDEXX Alertys OnFarm Pregnancy Test (lateral flow) and compare the accuracy of all three commercial PAG assays to transrectal ultrasonography and 2) to determine the postpartum interval necessary for clearance of pregnancy-associated glycoproteins from the previous pregnancy to avoid false positives. In study 1, blood samples from previously identified pregnant Bos taurus females from six different herds (nulliparous n = 1,205 and multiparous n = 1,539; samples collected between d 27 to 285 of gestation over a three-year period) were utilized. In study 2, postpartum females (primiparous n = 48 and multiparous n = 66) from one herd were utilized: (n = 1,066; samples collected weekly for up to 12 weeks postpartum). In study 1, level of agreement between different methods of pregnancy detection was determined by Pearson's correlation and Kappa scores. In study 2, data were analyzed as a repeated measure using the MIXED procedure of SAS with main effects of parity, days postpartum (dpp), and parity by days postpartum, then data were analyzed further using the REG procedure of SAS. In study 1, transrectal ultrasonography and lateral flow were positively correlated (r = 0.77; P <0.01), with 92.4% agreement. In study 2, the abundance of absorbance of PAGs rapidly decreased from 0 to 50 days postpartum, then continued to gradually decrease (P <0.01; r = 0.90). Prior to 42 days postpartum, PAG concentrations were sufficiently elevated resulting in false positive readings in all assays. In conclusion, there is very good agreement between transrectal ultrasonography and PAG assays, but likelihood of false positive results are highif assays are performed fewer than 42 days postpartum.

Impact of redefining statistical significance on P-hacking and false positive rates: An agent-based model.

In recent years, concern has grown about the inappropriate application and interpretation of P values, especially the use of P<0.05 to denote "statistical significance" and the practice of P-hacking to produce results below this threshold and selectively reporting these in publications. Such behavior is said to be a major contributor to the large number of false and non-reproducible discoveries found in academic journals. In response, it has been proposed that the threshold for statistical significance be changed from 0.05 to 0.005. The aim of the current study was to use an evolutionary agent-based model comprised of researchers who test hypotheses and strive to increase their publication rates in order to explore the impact of a 0.005 P value threshold on P-hacking and published false positive rates. Three scenarios were examined, one in which researchers tested a single hypothesis, one in which they tested multiple hypotheses using a P<0.05 threshold, and one in which they tested multiple hypotheses using a P<0.005 threshold. Effects sizes were varied across models and output assessed in terms of researcher effort, number of hypotheses tested and number of publications, and the published false positive rate. The results supported the view that a more stringent P value threshold can serve to reduce the rate of published false positive results. Researchers still engaged in P-hacking with the new threshold, but the effort they expended increased substantially and their overall productivity was reduced, resulting in a decline in the published false positive rate. Compared to other proposed interventions to improve the academic publishing system, changing the P value threshold has the advantage of being relatively easy to implement and could be monitored and enforced with minimal effort by journal editors and peer reviewers.

Quiz CORRECT ANSWER TO THE QUIZ. CHECK YOUR DIAGNOSIS Prostatic paraganglia-hyperplasia - ahistological mimic ofintraprostatic adipose tissue.

Prostatic paraganglia (PP) can simulate adenocarcinoma's fused gland pattern, and adifferential diagnostic panel is developed. Their differential diagnosis with benign prostatic lesions has been largely unreported. Intraprostatic adipose tissue (IPAT) is seen extremely rarely in prostatic specimens, but it must be known, to avoid false positive results for extraprostatic fat carcinomatous invasion in needle biopsy specimens. We present one case from 100 randomly selected radical prostatectomy specimens in which our diagnosis evolved from IPAT to PP-hyperplasia, after additional immunohistochemical investigations. Thepresence ofPP-hyperplasia, with both parenchymal and neurovascular bundle location, and its differential diagnosis with IPAT has not been previously reported.

Clinical Impact of a Local Triage System Using the Emergent Large Vessel Occlusion Screen with a Rotation System of Thrombectomy-Capable Hospitals.

Early intervention with mechanical thrombectomy (MT) is expected to improve the functional outcome in patients with large vessel occlusion (LVO); however, a method for the effective detection of these patients in a prehospital setting and early transport to MT-capable hospitals has not been established. This study aimed to analyze the clinical impact and diagnostic performance of the emergent large vessel occlusion (ELVO) screen and its influence on the transportation time. The emergency medical services (EMS) in one of the secondary medical areas in Akita, Japan, introduced a prehospital triage system employing an ELVO screen and a rotation system of three MT-capable hospitals on December 1, 2021. Patients who were transferred to each of the three hospitals involved in the rotation system according to a predefined priority list from December 2021 to November 2022 were included in the triage group. Patients who underwent MT in the three hospitals before the introduction of the triage system were assigned to the pre-triage group. We compared the transportation time parameters between the two groups and analyzed the performance of the ELVO screen for the diagnosis of LVOs. This study was approved by the institutional review boards of all three hospitals. Time parameters were compared between the 37 and 42 patients who underwent MT and had detailed data in the triage (n = 351) and pre-triage (n = 43) groups, respectively. The time from door to puncture tended to decrease in the triage group in all hospitals, with one hospital showing a statistically significant shortening of 14 min (p = 0.018). In the triage group, 209 ELVO screen-positive patients were present, with 60 (28.7%) of these having LVO. The sensitivity, specificity, positive and negative predictive values, and area under the curve of the ELVO screen to detect LVO under the present triage system were 87.0%, 47.2%, 28.7%, 93.7%, and 0.671, respectively. The present study demonstrated that the introduction of a triage system may have shortened the time required for MT. ELVO screen may be considered a useful marker for screening LVO in prehospital settings in terms of the sensitivity and negative predictive value; however, further improvement may be necessary to reduce the rate of false positive results.

Quantitative Real-Time Polymerase Chain Reaction May Serve as a Useful Adjunct to Conventional Culture in The Detection of Cutibacterium acnes in the Glenohumeral Joint: A Study of 100 Consecutive Patients.

Synovial fluid or tissue culture is the current gold standard for diagnosis of infection, but Cutibacterium acnes (C. acnes) is a frequent cause of shoulder PJI and is a notoriously fastidious organism. The purpose of this study was to compare quantitative real-time polymerase chain reaction (qRT-PCR) to standard culture as a more rapid, sensitive means of identifying C. acnes from the glenohumeral joint. We hypothesized that qRT-PCR would be more effective than standard culture at identifying C. acnes and would have greater sensitivity and specificity for detecting infection. This was a prospective observational study with 100 consecutive patients undergoing arthroscopic or open shoulder surgery with known positive and negative controls. Intraoperatively, synovial fluid and tissue was obtained for C. acnes qRT-PCR and results were blinded to the gold standard microbiology cultures. Clinical review demonstrated 3 patients (3%) with positive cultures, none of which were positive for C. acnes. Of the samples tested by the C. acnes qRT-PCR standard curve, 12.2% of tissue samples and 4.5% of fluid samples were positive. Culture sensitivity was 60.0%, specificity was 100.0%, PPV was 100.0%, and NPV was 97.9%. C. acnes qRT-PCR standard curve sensitivity, specificity, PPV, and NPV was 60.0%, 90.3%, 25.0%, and 97.7% respectively for tissue specimens and 0%, 95.2%, 0%, and 95.2% respectively, for fluid specimens. For combination of culture and tissue qRT-PCR, the sensitivity, specificity, PPV and NPV was 100%, 90.3%, 35.7%, and 100%, respectively. We report that qRT-PCR for C. acnes identified the organism more frequently than conventional culture. While these findings demonstrate the potential utility of qRT-PCR, the likelihood of false positive results of qRT-PCR should be considered. Thus, qRT-PCR may be useful as an adjuvant to current gold standard workup of synovial fluid or tissue culture for the diagnosis of infection.

3D ARCNN: An Asymmetric Residual CNN for False Positive Reduction in Pulmonary Nodule.

Lung cancer is with the highest morbidity and mortality, and detecting cancerous lesions early is essential for reducing mortality rates. Deep learning-based lung nodule detection techniques have shown better scalability than traditional methods. However, pulmonary nodule test results often include a number of false positive outcomes. In this paper, we present a novel asymmetric residual network called 3D ARCNN that leverages 3D features and spatial information of lung nodules to improve classification performance. The proposed framework uses an internally cascaded multi-level residual model for fine-grained learning of lung nodule features and multi-layer asymmetric convolution to address the problem of large neural network parameters and poor reproducibility. We evaluate the proposed framework on the LUNA16 dataset and achieve a high detection sensitivity of 91.6%, 92.7%, 93.2%, and 95.8% for 1, 2, 4, and 8 false positives per scan, respectively, with an average CPM index of 0.912. Quantitative and qualitative evaluations demonstrate the superior performance of our framework compared to existing methods. 3D ARCNN framework can effectively reduce the possibility of false positive lung nodules in the clinical.

Detection of feline immunodeficiency virus by neutral red-based loop-mediated isothermal amplification assay.

Feline immunodeficiency virus (FIV) is a retroviral pathogen globally responsible for immunodeficiency disease in cats. However, the current diagnosis based on antibody detection has limitations and can also produce false-positive results. This study aimed to develop a one-pot loop-mediated isothermal amplification (LAMP) process integrated with neutral red (NR-LAMP) assay for detection of FIV proviral DNA. We developed a one-pot, gag gene-based NR-LAMP for convenient, rapid, specific, and sensitive colorimetric inspection of FIV proviral DNA. The developed NR-LAMP was capable of amplifying at an optimum temperature of 65°C for 40 min. No cross-amplification was detected between FIV and other feline viruses tested, indicating the high specificity (98.44%) of the novel FIV-LAMP primer. Our NR-LAMP assay has a detection limit of 4.2 × 101 copies/μL. A total of 80 clinical samples with a background of FIV infection were collected and tested using the proposed method. The NR-LAMP assay showed a high sensitivity of 100% compared to conventional polymerase chain reaction assay. These results support the suitability of NR-LAMP as a potential future alternative clinical molecular approach for further use in the diagnosis of FIV-infected cats.

The usefulness of anti-HCV signal to cut-off ratio in predicting hepatitis C viremia and the effect of genotype differences on signal to cut-off ratio.

In the hepatitis C virus (HCV) diagnostic algorithm, an anti-HCV screening test is recommended first. In countries with low HCV prevalence, anti-HCV testing can often give false-positive results. This may lead to unnecessary retesting, increased costs, and psychological stress for patients. In this study, the most appropriate S/Co (signal-cutoff) value to predict HCV viremia in anti-HCV test(+) individuals was determined, and the effect of genotype differences was evaluated. Of the 96,515 anti-HCV tests performed between 2020 and 2023, 934 were reactive. A total of 332 retests and 65 patients without HCV-ribonucleic acid (RNA) analysis were excluded. Demographic data were calculated for 537 patients, and 130 patients were included in the study. The average age of 537 patients was 55±18 years, and 57.1% were women. The anti-HCV positivity rate was 0.62% (602/96,515), and the actual anti-HCV positivity rate was 0.13% (130/96,515). Anti-HCV levels were higher in HCV-RNA(+) patients than in HCV-RNA-negative individuals (p<0.0001) (Table 1). Receiver operating characteristic curve analysis identified the optimal S/Co value to be 10.86 to identify true positive cases. Sensitivity was 96.1%, specificity was 61.2%, positive predictive value (PPV) was 44.2%, and negative predictive value (NPV) was 98% (Figure 2). A total of 107 (82.3%) of the patients were identified as GT1, and the most common subtype was GT1b (n=100). If anti-HCV S/Co is ≥10.86, direct HCV RNA testing may be recommended; However, the possibility of false positivity should be considered in patients with a S/Co value below 10.86.

Updated DPYD HapB3 haplotype structure and implications for pharmacogenomic testing.

The DPYD gene encodes dihydropyrimidine dehydrogenase, the rate-limiting enzyme for the metabolism of fluoropyrimidines 5-fluorouracil and capecitabine. Genetic variants in DPYD have been associated with altered enzyme activity, therefore accurate detection and interpretation is critical to predict metabolizer status for individualized fluoropyrimidine therapy. The most commonly observed deleterious variation is the causal variant linked to the previously described HapB3 haplotype, c.1129-5923C>G (rs75017182) in intron 10, which introduces a cryptic splice site. A benign synonymous variant in exon 11, c.1236G>A (rs56038477) is also linked to HapB3 and is commonly used for testing. Previously, these single-nucleotide polymorphisms (SNPs) have been reported to be in perfect linkage disequilibrium (LD); therefore, c.1236G>A is often utilized as a proxy for the function-altering intronic variant. Clinical genotyping of DPYD identified a patient who had c.1236G>A, but not c.1129-5923C>G, suggesting that these two SNPs may not be in perfect LD, as previously assumed. Additional individuals with c.1236G>A, but not c.1129-5923C>G, were identified in the Children's Mercy Data Warehouse and the All of Us Research Program version 7 cohort substantiating incomplete SNP linkage. Consequently, testing only c.1236G>A can generate false-positive results in some cases and lead to suboptimal dosing that may negatively impact patient therapy and prospect of survival. Our data show that DPYD genotyping should include the functional variant c.1129-5923C>G, and not the c.1236G>A proxy, to accurately predict DPD activity.

Development of a PCR Method to Detect a Mysid Species Causing False Positives in Tests for Crustacean Allergens

Mysids are small crustaceans that are closely related to shrimp/prawns and crabs but not subject to food allergen labeling requirements for raw materials. In the past, a processed food that contained Japanese smelt (wakasagi) was suspected of producing a false-positive result in shrimp/prawn and crab allergen test because of the presence of consumed mysids. However, there was no reported methods to confirm mysid presence. Therefore, we developed a PCR method to detect mysids. The developed PCR method had high specificity for a mysid species, with no amplification observed from samples of shrimp, crab, krill, mantis shrimp, or the meat of Japanese smelt. In addition, DNA extracted from the internal organs of Japanese smelt was amplified by this PCR method, and sequencing revealed mysid DNA. This confirmed that mysids remained in the internal organs of Japanese smelt following consumption. This PCR method for mysid detection even amplified Japanese smelt-containing processed food samples that were suspected to have produced a false-positive result in shrimp/prawn and crab ELISA. Thus, this PCR method would enable to detect such false positives are caused by mysid contamination.

Immunology Status of Patients During Kidney Transplant.

The immunology status of a patient has a crucial role in kidney transplant. We investigated the effectiveness of a desensitization protocol, guided by the immunology status of patients, for kidney transplant candidates. Antibody screening for human leukocyte antigens was conducted with the Luminex single-antigen microsphere bead assay method for 34 patients from June 2021 to June 2022. Donor human leukocyte antigen genotypes at 8 loci (A*, B*, С*, DRB1*, DQA1*, DQB1*, DPA1*, and DPB1*) were determined, to correlate the specificities of recipient human leukocyte antigen antibodies with donor antigens and identify unacceptable donor antigen combinations. Specialized immunology studies measured panel reactive antibody levels and human leukocyte antigen class I and class II antibodies. A crossmatch compatibility test using complementdependent cytotoxicity was conducted. Of the 34 patients, 10 completed all 3 stages of the desensitization therapy. Most patients experienced decreased sensitization to human leukocyte antigen class I and class II antibodies. Two patients achieved complete clearance of A1 and DQ5 antibodies, respectively, whereas 1 patient exhibited an increase in donor-specific antibody mean fluorescence intensity. Prior to desensitization therapy, the crossmatch compatibility test yielded positive results with T and B lymphocytes. After completing the therapy, the crossmatch test showed negative results in 4 cases with T lymphocytes and positive results with B lymphocytes. Plasmapheresis sessions effectively reduced circulating antibodies. However, the combination of rituximab and plasmapheresis alone did not achieve a negative crossmatch test required for kidney transplant. It is crucial to assess the reduction of donor-specific antibody quantity, considering both the percentage and the mean fluorescence intensity. To avoid false-positive results in crossmatch analysis, drug half-life must be considered. Laboratories should have various crossmatch techniques, such as flow cytometry and single-antigen microsphere bead assay technology, available for research and urgent cases that require crossmatch analysis.

Prevalence of Toxoplasma gondii IgM and IgG positive cats in Los Angeles County, California.

The objective of this study was to determine the prevalence of Toxoplasma gondii IgM and IgG positive cats in Los Angeles County, California. T gondii antibodies are common in sera from cats in most reported studies around the world. Although the majority of infected cats never develop clinical disease, development of acute infection and recrudescence of latent infection secondary to immunosuppression has been reported. Knowledge of the serologic status of T gondii may be important when considering immunosuppressive treatments. T gondii IgM and IgG antibody titers were measured in 225 cats. Sera from owned cats tested at a multispecialty veterinary hospital were included both retrospectively and prospectively (n = 125). Sera from feral cats tested through a collaborating humane society were included prospectively (n = 100). Of the 13 (5.8%) cats with IgM titers, 10 were positive at the minimal cut-off titer (1:64), one cat was clinically ill and none were currently positive for IgG antibodies, suggesting false-positive results for nine cats, giving an adjusted IgM prevalence rate of 1.8% (95% CI 0.7-4.5). A total of five (2.2%) cats were positive for IgG antibodies and no cat was positive for both antibodies. Most studies of T gondii antibodies in cat sera from California have shown higher prevalence rates, suggesting the cats in this municipality have a low risk of exposure. The study emphasizes that serological test results do not necessarily correlate to the presence of clinical illness.

Hemoglobinopathy as a Rare Differential Disease for Low Oxygen Saturation by Pulse Oximetry: A Case Report and Literature Review.

Pulse oximetry is used to screen for respiratory failure in dyspnea patients. However, pulse oximetry can yield false-positive results in certain situations. Unstable hemoglobinopathy is a disease in which mutations in the globin-encoding gene result in abnormal globin chain production, causing low percutaneous oxygen saturation (SpO2) levels due to changes in hemoglobin absorbance and oxygen affinity. We identified a new family lineage of Hb Hirosaki in an adult patient with chronic obstructive pulmonary disease, dyspnea, and low SpO2. According to our literature review, only a few cases of unstable hemoglobinopathy have been reported in adults. Most patients with unstable hemoglobinopathy are asymptomatic, and those with dyspnea often have respiratory diseases or severe anemia. To differentiate unstable hemoglobinopathy, an appropriate assessment of the discrepancy between SpO2 values and arterial blood gas analysis results is important.