scholarly journals Commercial Laboratory IgM Testing forToxoplasma gondiiin Pregnancy: A 20-Year Experience

2005 ◽  
Vol 13 (3) ◽  
pp. 151-153 ◽  
Author(s):  
David J. Garry ◽  
Andrew Elimian ◽  
Vandy Wiencek ◽  
David A. Baker
Keyword(s):  
Predictive Value ◽  
False Positive ◽  
False Positive Rate ◽  
Reference Laboratory ◽  
Antibody Testing ◽  
Commercial Laboratory ◽  
Laboratory Results ◽  
Positive Rate ◽  
Acute Toxoplasmosis ◽  
Positive Results

Objective.This study was performed to review the clinical utility of commercial laboratoryToxoplasmosis-specific IgM testing during pregnancy and outcomes of the gestation at our institution.Methods.A retrospective review of all women referred for suspected acuteToxoplasma gondiiinfection during pregnancy from 1984 through 2004 was performed. Women were diagnosed with suspected acute toxoplasmosis based on commercial laboratory serologic antibody testing. All women had blood sent to a recognized reference laboratory for antibody testing within 2 weeks of the commercial laboratory results. The study protocol was approved by the Institutional Review Board. Chi-square analysis were used with a significance ofP< .05.Results.A total of 130 women were evaluated during the study period with 116 IgM positive results from the commercial laboratories. The commercial laboratory antibodies were as follows: IgM positive with IgG negative (n= 20), IgM positive with IgG positive (n= 96), and IgM negative with IgG positive (n= 14). There was a significant reduction in the IgM positive results when comparing commercial laboratory (n= 116) with the reference laboratory results (n= 28;p< .001). Acute toxoplasmosis infection was diagnosed in 7 (5%) of the women. All cases of acute toxoplasmosis infection had a positive commercial laboratory IgM result. The false positive rate for the commercial laboratory IgM was 88.6% and the diagnostic indices were sensitivity 100%, specificity 11.4%, positive predictive value 6% and negative predictive value 100%.Conclusion.Commercial laboratoryToxoplasmosis-specific IgM is associated with a high false positive rate. The commercial and reference laboratory IgM results identified all cases of acute toxoplasmosis infection. Commercial laboratories reflexively obtaining reference laboratory confirmation of positive results could reduce costs associated with testing, referrals, retesting, and invasive procedures.

scholarly journals Evaluation of optimal urine screening and confirmation cut-off values for opiates, at a national reference laboratory

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Çiğdem Karakükcü ◽  
Mehmet Zahid Çıracı ◽  
Derya Kocer ◽  
Mine Yüce Faydalı ◽  
Muhittin Abdulkadir Serdar
Keyword(s):  
False Positive ◽  
False Positive Rate ◽  
False Negative ◽  
Urine Samples ◽  
Reference Laboratory ◽  
National Reference Laboratory ◽  
Urine Screening ◽  
National Reference ◽  
Positive Rate ◽  
Sensitivity Specificity

Abstract Objectives To obtain optimal immunoassay screening and LC-MS/MS confirmation cut-offs for opiate group tests to reduce false positive (FP) and false negative (FN) rates. Methods A total of 126 urine samples, −50 opiate screening negative, 76 positive according to the threshold of 300 ng/mL by CEDIA method – were confirmed by a full-validated in-house LC-MS/MS method. Sensitivity, specificity, FP, and FN rates were determined at cut-off concentrations of both 300 and 2,000 ng/mL for morphine and codeine, and 10 ng/mL for heroin metabolite 6-mono-acetyl-morphine (6-MAM). Results All CEDIA opiate negative urine samples were negative for morphine, codeine and 6-MAM. Although sensitivity was 100% for each cut-off; specificity was 54.9% at CEDIA cut-off 300 ng/mL vs. LC-MS/MS cut-off 300 ng/mL and, 75% at CEDIA cut-off 2,000 ng/mL vs. LC-MS/MS cut-off 2,000 ng/mL. False positive rate was highest (45.1%) at CEDIA cut-off 300 ng/mL. At CEDIA cut-off 2,000 ng/mL vs. LC-MS/MS cut-off 300 ng/mL, specificity increased to 82.4% and FP rate decreased to 17.6%. All 6-MAM positive samples had CEDIA concentration ≥2,000 ng/mL. Conclusions 2,000 ng/mL for screening and 300 ng/mL for confirmation cut-offs are the most efficient thresholds for the lowest rate of FP opiate results.

scholarly journals Identification of newborns at risk for autism using electronic medical records and machine learning

2019 ◽  
Author(s):  
Rayees Rahman ◽  
Arad Kodesh ◽  
Stephen Z Levine ◽  
Sven Sandin ◽  
Abraham Reichenberg ◽  
...  
Keyword(s):  
Machine Learning ◽  
Autism Spectrum Disorder ◽  
Positive Predictive Value ◽  
Electronic Medical Records ◽  
Predictive Value ◽  
False Positive ◽  
Medical Records ◽  
False Positive Rate ◽  
Autism Spectrum ◽  
Positive Rate

AbstractImportanceCurrent approaches for early identification of individuals at high risk for autism spectrum disorder (ASD) in the general population are limited, where most ASD patients are not identified until after the age of 4. This is despite substantial evidence suggesting that early diagnosis and intervention improves developmental course and outcome.ObjectiveDevelop a machine learning (ML) method predicting the diagnosis of ASD in offspring in a general population sample, using parental electronic medical records (EMR) available before childbirthDesignPrognostic study of EMR data within a single Israeli health maintenance organization, for the parents of 1,397 ASD children (ICD-9/10), and 94,741 non-ASD children born between January 1st, 1997 through December 31st, 2008. The complete EMR record of the parents was used to develop various ML models to predict the risk of having a child with ASD.Main outcomes and measuresRoutinely available parental sociodemographic information, medical histories and prescribed medications data until offspring’s birth were used to generate features to train various machine learning algorithms, including multivariate logistic regression, artificial neural networks, and random forest. Prediction performance was evaluated with 10-fold cross validation, by computing C statistics, sensitivity, specificity, accuracy, false positive rate, and precision (positive predictive value, PPV).ResultsAll ML models tested had similar performance, achieving an average C statistics of 0.70, sensitivity of 28.63%, specificity of 98.62%, accuracy of 96.05%, false positive rate of 1.37%, and positive predictive value of 45.85% for predicting ASD in this dataset.Conclusion and relevanceML algorithms combined with EMR capture early life ASD risk. Such approaches may be able to enhance the ability for accurate and efficient early detection of ASD in large populations of children.Key pointsQuestionCan autism risk in children be predicted using the pre-birth electronic medical record (EMR) of the parents?FindingsIn this population-based study that included 1,397 children with autism spectrum disorder (ASD) and 94,741 non-ASD children, we developed a machine learning classifier for predicting the likelihood of childhood diagnosis of ASD with an average C statistic of 0.70, sensitivity of 28.63%, specificity of 98.62%, accuracy of 96.05%, false positive rate of 1.37%, and positive predictive value of 45.85%.MeaningThe results presented serve as a proof-of-principle of the potential utility of EMR for the identification of a large proportion of future children at a high-risk of ASD.

scholarly journals Modelling science trustworthiness under publish or perish pressure

2018 ◽  
Vol 5 (1) ◽  
pp. 171511 ◽  
Author(s):  
David Robert Grimes ◽  
Chris T. Bauch ◽  
John P. A. Ioannidis
Keyword(s):  
Phenomenological Model ◽  
False Positive ◽  
Null Hypothesis ◽  
False Positive Rate ◽  
Scientific Publication ◽  
Negative Consequences ◽  
Publish Or Perish ◽  
Positive Rate ◽  
Positive Results ◽  
Scientific Endeavour

Scientific publication is immensely important to the scientific endeavour. There is, however, concern that rewarding scientists chiefly on publication creates a perverse incentive, allowing careless and fraudulent conduct to thrive, compounded by the predisposition of top-tier journals towards novel, positive findings rather than investigations confirming null hypothesis. This potentially compounds a reproducibility crisis in several fields, and risks undermining science and public trust in scientific findings. To date, there has been comparatively little modelling on factors that influence science trustworthiness, despite the importance of quantifying the problem. We present a simple phenomenological model with cohorts of diligent, careless and unethical scientists, with funding allocated by published outputs. This analysis suggests that trustworthiness of published science in a given field is influenced by false positive rate, and pressures for positive results. We find decreasing available funding has negative consequences for resulting trustworthiness, and examine strategies to combat propagation of irreproducible science.

Properly collected plasma metanephrines excludes PPGL after false positive screening tests

2021 ◽  
Author(s):  
Gregory A Kline ◽  
Jessica Boyd ◽  
Brenda Polzin ◽  
Adrian Harvey ◽  
Janice L Pasieka ◽  
...  
Keyword(s):  
False Positive ◽  
Adrenal Mass ◽  
Chart Review ◽  
False Positive Rate ◽  
Total Positivity ◽  
Screening Tests ◽  
Positive Rate ◽  
Plasma Metanephrines ◽  
Positive Results ◽  
Urine Metanephrines

Abstract Context False positive results are common for pheochromocytoma/paraganglioma(PPGL) real-world screening. Objective Determine the correlation between screening urine and seated plasma metanephrines in outpatients where PPGL was absent, compared to meticulously prepared and supine-collected plasma metanephrines with age-adjusted references. Design Retrospective cohort study Setting Databases from a single-provider provincial laboratory(2012-2018), a validated PPGL registry and a manual chart review from a specialized endocrine testing unit. Patients PPGL registry data excluded known PPGL cases from the laboratory database. Outpatients having both urine and plasma metanephrines &lt;90 days apart. Methods The correlation between urine and seated plasma measures along with the total positivity rate. All cases of plasma metanephrines drawn in the endocrine unit were reviewed for test indication and test positivity rate. Results There were 810 non-PPGL pairs of urine and plasma metanephrines in the laboratory database; 46.1% of urine metanephrines were reported high. Of seated outpatient plasma metanephrines drawn a median of 5.9 days later, 19.2% were also high (r=0.33 and 0.50 for normetanephrine and metanephrine, respectively). In contrast, the meticulously prepared and supine collected patients(n=139, 51% prior high urine metanephrines) had &lt;3% rate of abnormal high results in patients without known PPGL/adrenal mass. Conclusions There was a poor-to-moderate correlation between urine and seated plasma metanephrines. Up to 20% of those with high urine measures also had high seated plasma metanephrines in the absence of PPGL. Properly prepared and collected supine plasma metanephrines had a false positive rate of &lt;3% in the absence of known PPGL/adrenal mass.

Venous Flow Coupler in Head and Neck Free Flap Reconstruction

2020 ◽  
pp. 019459982095309
Author(s):  
Scott H. Troob ◽  
Quinn Self ◽  
Deniz Gerecci ◽  
Macgregor Hodgson ◽  
Javier González-Castro ◽  
...  
Keyword(s):  
Free Flap ◽  
Predictive Value ◽  
False Positive ◽  
False Positive Rate ◽  
Case Series ◽  
Arterial Flow ◽  
Retrospective Case ◽  
Venous Flow ◽  
Retrospective Case Series ◽  
Positive Rate

Objective To describe the utility of venous flow couplers in monitoring free tissue flaps in the immediate postoperative setting. Study Design Retrospective case series. Setting Otolaryngology department at a single tertiary care institution. Methods A retrospective case series of free flap reconstructions in which venous flow couplers were employed to supplement flap monitoring. All free flap cases performed over the past 4 years were reviewed. Inclusion criteria were venous flow coupler and arterial flow Doppler monitored for 5 days postoperatively. Results From July 2014 through May 2018, the venous flow coupler was used with the arterial flow Doppler and clinical monitoring in 228 cases. Eleven cases did not meet criteria for inclusion; thus, 217 cases were analyzed. Twenty cases (9.2%) returned to the operating room with concern for flap compromise, and 16 were salvaged. The combination of venous flow coupler and arterial flow Doppler identified 19 of these flaps. Venous flow couplers identified 5 compromised flaps before there was an arterial signal change, and all were salvaged. Additionally, there was a 24.1% false-positive rate when 2 venous flow couplers were used in parallel. For the venous flow coupler, the positive predictive value was 64.3% and the negative predictive value, 98.9%. The false-positive rate in the series was 5.1%. The sensitivity was 90% and the specificity, 94.9%. Conclusion The venous flow coupler is able to detect venous thrombosis in the absence of arterial thrombosis and may contribute to improved flap salvage rates.

An approach to optimize delta checks in test panels – The effect of the number of rules included

2020 ◽  
Vol 57 (3) ◽  
pp. 215-222 ◽  
Author(s):  
Rui Zhen Tan ◽  
Corey Markus ◽  
Tze Ping Loh
Keyword(s):  
False Positive ◽  
False Positive Rate ◽  
Original Data ◽  
Random Permutation ◽  
Full Blood Count ◽  
Hypothesis Tests ◽  
Data Set ◽  
Laboratory Results ◽  
Positive Rate ◽  
Common Laboratory

Objectives The interpretation of delta check rules in a panel of tests should be different to that at the single analyte level, as the number of hypothesis tests conducted (i.e. the number of delta check rules) is greater and needs to be taken into account. Methods De-identified paediatric laboratory results were extracted, and the first two serial results for each patient were used for analysis. Analytes were grouped into four common laboratory test panels consisting of renal, liver, bone and full blood count panels. The sensitivities and specificities of delta check limits as discrete panel tests were assessed by random permutation of the original data-set to simulate a wrong blood in tube situation. Results Generally, as the number of analytes included in a panel increases, the delta check rules deteriorate considerably due to the increased number of false positives, i.e. increased number hypothesis tests performed. To reduce high false-positive rates, patient results may be rejected from autovalidation only if the number of analytes failing the delta check limits exceeds a certain threshold of the total number of analytes in the panel (N). Our study found that the use of the ([Formula: see text] rule) for panel results had a specificity >90% and sensitivity ranging from 25% to 45% across the four common laboratory panels. However, this did not achieve performance close to some analytes when considered in isolation. Conclusions The simple [Formula: see text] rule reduces the false-positive rate and minimizes unnecessary, resource-intensive investigations for potentially erroneous results.

Protein Expression Signatures Determined by Reverse Phase Proteins Arrays (RPPA) Accurately Predict FLT3-ITD Mutation Status in AML.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2398-2398
Author(s):  
Steven M. Kornblau ◽  
YiHua Qiu ◽  
Wenjing Chen ◽  
Srdan Verstovsek ◽  
Kevin R. Coombes ◽  
...  
Keyword(s):  
Positive Predictive Value ◽  
Protein Expression ◽  
Mutation Analysis ◽  
Predictive Value ◽  
False Positive ◽  
False Positive Rate ◽  
Myelogenous Leukemia ◽  
Reverse Phase ◽  
Mutation Status ◽  
Positive Rate

Abstract We have used Reverse Phase Protein Arrays (RPPA) to perform proteomic profiling in Acute Myelogenous Leukemia (AML) focusing on cell cycle, apoptosis and signal transduction pathway proteins (ASH 2006, abstract #107). Protein expression signatures were derived from this dataset of 436 AML patients, analyzed for 30 total and 22 phopho- proteins. The predictive ability of these RPPA derived protein expression signatures has not been prospectively tested to determine if they are valid. This dataset presented an opportunity to validate this as there was a population of patients with known FLT3-ITD and D835 mutation status (n=297) and another population where the status was unknown (n=139), among which 55 had sufficient sample available for mutation analysis. Prior to performing the mutation analysis a predictive model was built using linear regression with part of the data utilized for training and the reminder for validation. The model was designed to predict for the presence of mutation, either ITD or D835, although there are differences int eh signature of each. The total population had 85 cases with FLT3-ITD and 15 with the D835 mutation. The optimal model that was developed, using 30%, 50% and 70% of the samples for training and the remainder for validation, had a median validation accuracy of 68%, 70% and 72% respectively. Prospective predictions of FLT3-ITD or D835 mutation status were then made for all samples lacking FLT3-ITD or D835 mutation data. Mutation analysis was then performed using PCR amplification followed by 2-D gel electrophoresis (FLT3-ITD) to evaluate for PCR product size, or sequencing (D835) on 55 samples. This revealed 9 cases with FLT3-ITD, 3 with a D835 mutation, 1 with both and 43 without mutation. Among these 55 cases the model correctly predicted that 8 of the 12 mutant cases would be mutant including 8 of 10 with a FLT3-ITD, but 0 of 2 with only the D835 mutation. Among the 43 wildtype cases 36 were accurately predicted to be wildtype, while 7 were incorrectly predicted to have the mutation mutant. This yields an overall accuracy (OA) of 80%, Sensitivity =66%, Specificity=90%, Positive Predictive Value (PPV) of 53%, False positive rate of (FPR) of 16%. Since most patients with FLT3-ITD have Diploid cytogenetics we also looked at the predictive accuracy of the protein expression signature in that population. Among 23 patients with Diploid cytogenetics the overall accuracy was OA) of 83%, Sensitivity =75%, Specificity=87%, Positive Predictive Value (PPV) of 75%, False positive rate of (FPR) of 13%. Since FLT3-ITD and D835 carry different prognostic impact, and had different protein expression signatures, greater accuracy might be achieved if separate models were developed for each mutation individually. The model demonstrated that RPPA derived protein expression signatures can accurately be used to predict mutation status providing the first prospective validation of protein expression signatures in AML.

Validation of Receptor-Binding Assays To Detect Antibiotics in Goat's Milk

2014 ◽  
Vol 77 (2) ◽  
pp. 308-313 ◽  
Author(s):  
M. C. BELTRÁN ◽  
M. BORRÀS ◽  
O. NAGEL ◽  
R. L. ALTHAUS ◽  
M. P. MOLINA
Keyword(s):  
Receptor Binding ◽  
False Positive ◽  
False Positive Rate ◽  
Quality Parameters ◽  
Lactation Period ◽  
Binding Assays ◽  
Goat’S Milk ◽  
Positive Rate ◽  
Goat's Milk ◽  
Positive Results

The suitability of different receptor-binding assays to detect antibiotics in raw goat's milk was investigated. Detection capability of most β-lactams and tetracyclines assessed applying the Betastar Combo, the SNAP Betalactam, the SNAP Tetracycline, and the Twinsensor tests was at or below maximum residue limits established by European legislation. Regarding test specificity, cross-reactions with antibiotics other than β-lactams and tetracyclines were not found, and no false-positive results were obtained for the Betastar Combo and the SNAP tests when bulk samples of goat's milk were analyzed. For the Twinsensor test, the false-positive rate was 1%. The performance of the Betastar Combo and the SNAP tests was practically unaffected by the milk quality parameters using individual samples of goat's milk collected at points throughout the entire lactation period (false-positive rate, ≤5%). However, a larger number of positive results were obtained by the Twinsensor test in this type of milk sample (&gt;10%), especially in the last weeks of lactation. Interferences related to the use of the preservative azidiol were not observed in any case. Neither were any significant differences found in relation to the interpretation method (visual versus instrumental) applied. In general, the response of the Betastar Combo, SNAP, and Twinsensor tests was optimal for the analysis of bulk caprine milk; thus, they may be used to monitor milk for the presence of β-lactam and tetracycline residues in quality control programs.

scholarly journals Use of a Disposable Water Filter for Prevention of False-Positive Results due to Nontuberculosis Mycobacteria in a Clinical Laboratory Performing Routine Acid-Fast Staining for Tuberculosis

2007 ◽  
Vol 73 (19) ◽  
pp. 6296-6298 ◽  
Author(s):  
Hui-Zin Tu ◽  
Chiao-Shan Chen ◽  
Tsi-Shu Huang ◽  
Wen-Kuei Huang ◽  
Yao-shen Chen ◽  
...  
Keyword(s):  
False Positive ◽  
Clinical Laboratory ◽  
Tap Water ◽  
False Positive Rate ◽  
Acid Fast Bacillus ◽  
Water Filter ◽  
Point Of Use ◽  
Positive Rate ◽  
Positive Results ◽  
Laboratory Water

ABSTRACT A point-of-use 0.2-μm filter was evaluated for elimination of nontuberculosis mycobacteria in laboratory water to reduce false-positive acid-fast bacillus staining results. Use of the point-of-use filter can significantly reduce the false-positive rate to 1.2% compared to samples treated with tap water (10.7%) and deionized water (8.7%).

Reduction in False-Positive PF4/Heparin Antibody Testing Following Implementation of a Latex Immunoturbidimetric Assay

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S34-S34
Author(s):  
Chiraag Gangahar ◽  
Daniel Webber ◽  
Ronald Jackups
Keyword(s):  
Clinical Judgment ◽  
Test Performance ◽  
False Positive ◽  
Clinical Laboratory ◽  
Turnaround Time ◽  
Serotonin Release ◽  
Reference Laboratory ◽  
Antibody Testing ◽  
Release Assay ◽  
Positive Results

Abstract Background Heparin-induced thrombocytopenia (HIT) is a life-threatening complication of exposure to heparin that is caused by autoantibodies against heparin-PF4 complexes. We recently changed our in-house HIT screening platform from a manual, daily batched ELISA (Stago-Asserochrom HPIA Immunoassay) to an automated, on-demand latex immunoturbidimetric assay (LIA, HemosIL HIT-Ab) and have also implemented a reflex from a positive LIA result to the confirmatory serotonin release assay (SRA). We compared the two methods in terms of utilization, test performance, and turnaround time. Methods Data were collected retrospectively from a 7-month period before (June-December 2017) and after (June-December 2018) implementation of the HemosIL LIA in the clinical laboratory at a large academic institution. This study includes consecutive test results from adults (median age: 64 years, range: 19-98 years) seen at our 1,300-bed main hospital. Test utilization, turnaround time (sample receipt to verification), and test performance characteristics were compared between the two methods. Repeat testing was excluded from the analysis. Samples with a positive result on the HemosIL LIA were reflexed to a serotonin release assay (SRA), performed at a large reference laboratory, whereas samples tested with the earlier ELISA assay were referred for SRA testing based upon clinical judgment. When performed, SRA was considered the gold standard for diagnosis of HIT. Results During the 7 months before and after switching methods, there were 109 of 594 (18.4%) positive ELISA results and 45 of 523 (8.6%) positive LIA results. Only 90 of 109 (82%) of the positive results from the ELISA HIT Ab test were sent out by clinicians for SRA testing, whereas 45 of 45 (100%) of the positive results from LIA testing were reflexed to SRA per protocol. Although fewer LIA tests were sent out for SRA testing, there were an equal number of SRA-confirmed cases of HIT with the ELISA (PPV: 16/90 [17.8%]) and LIA methods (PPV: 16/45 [35.6%]), resulting in a high positive predictive value (PPV) with the newly implemented method. Not only was the PPV higher with the LIA test, but it had a significantly shorter mean turnaround time of 96 minutes compared to the ELISA TAT of 1,234 minutes (P < .0001). Conclusions With the new testing protocol, patients received results faster (average 96-minute TAT) and had fewer false-positive results (74/594 pre vs 29/523 post), with no apparent reduction in detection of true-positive cases of HIT (16/594 pre vs 16/523 post).

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