scholarly journals False-Negative Results from Point-of-Care Qualitative Human Chorionic Gonadotropin (hCG) Devices Caused by Excess hCGβ Core Fragment Vary with Device Lot Number

2009 ◽  
Vol 55 (10) ◽  
pp. 1885-1886 ◽  
Author(s):  
Ann M Gronowski ◽  
Michelle Powers ◽  
Ulf H Stenman ◽  
Lori Ashby ◽  
Mitchell G Scott
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Point Of Care ◽  
False Negative ◽  
Core Fragment ◽  
Negative Results ◽  
False Negative Results

scholarly journals False-Negative Results in Point-of-Care Qualitative Human Chorionic Gonadotropin (hCG) Devices Due to Excess hCGβ Core Fragment

2009 ◽  
Vol 55 (7) ◽  
pp. 1389-1394 ◽  
Author(s):  
Ann M Gronowski ◽  
Mark Cervinski ◽  
Ulf-Håkan Stenman ◽  
Alison Woodworth ◽  
Lori Ashby ◽  
...  
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Point Of Care ◽  
False Negative ◽  
The Core ◽  
Core Fragment ◽  
Negative Results ◽  
False Negative Results ◽  
Positive Results ◽  
Urine Specimens

Abstract Background: During pregnancy, human chorionic gonadotropin (hCG) immunoreactivity in urine consists of intact hCG as well as a number of hCG variants including the core fragment of hCGβ (hCGβcf). We identified 3 urine specimens with apparent false-negative results using the OSOM® hCG Combo Test (Genzyme Diagnostics) qualitative hCG device and sought to determine whether an excess of 1 of the fragments or variants might be the cause of the interference. Methods: We measured concentrations of hCG variants in the urine from 3 patients with apparent false-negative hCG results. Purified hCG variants were added to urines positive for hCG and tested using the OSOM, ICON® 25 hCG (Beckman Coulter), and hCG Combo SP® Brand (Cardinal Health) devices. Results: Dilution of these 3 urine samples resulted in positive results on the OSOM device. Quantification of hCG variants in each of the 3 patient urine specimens demonstrated that hCGβcf occurred in molar excess of intact hCG. Addition of purified hCGβcf to hCG-positive urines caused false-negative hCG results using the OSOM and ICON qualitative urine hCG devices. Conclusions: Increased concentrations of hCGβcf can cause false-negative results on the OSOM and ICON qualitative urine hCG devices. .

scholarly journals Screening Method to Evaluate Point-of-Care Human Chorionic Gonadotropin (hCG) Devices for Susceptibility to the Hook Effect by hCG β Core Fragment: Evaluation of 11 Devices

2014 ◽  
Vol 60 (4) ◽  
pp. 667-674 ◽  
Author(s):  
Robert D Nerenz ◽  
Haowei Song ◽  
Ann M Gronowski
Keyword(s):  
Chorionic Gonadotropin ◽  
Healthcare Professionals ◽  
Point Of Care ◽  
False Negative ◽  
Screening Method ◽  
Core Fragment ◽  
Negative Results ◽  
Hook Effect ◽  
False Negative Results ◽  
Wide Range

Abstract BACKGROUND The predominant hCG variant in urine, hCG β core fragment (hCGβcf), has been demonstrated to cause false-negative results in qualitative point-of-care (POC) hCG devices. This is a major concern for healthcare professionals using POC pregnancy tests. We developed a screening method to evaluate qualitative POC hCG devices for their susceptibility to inhibition by hCGβcf. Using this method, we evaluated the performance of 11 commonly used devices. METHODS A wide range of purified hCG and hCGβcf concentrations were mixed and tested on 2 POC devices. By use of those results, a screening method was defined and 9 additional POC devices were evaluated. Two solutions containing (a) 500 pmol/L (171 IU/L) intact hCG with 0 pmol/L hCGβcf and (b) 500 pmol/L intact hCG with 500 000 pmol/L hCGβcf were used to screen all POC devices. RESULTS The OSOM and Cen-Med Elite devices were found to be most susceptible to false-negative results due to hCGβcf. The BC Icon 20 and the Alere were the least susceptible. The remaining 7 were moderately affected. Devices that gave the strongest signal with hCGβcf alone were those that were least likely to show a hook effect. CONCLUSIONS The screening method put forth here can be used by device users and manufacturers to evaluate POC devices for inhibition by hCGβcf. Of 11 devices evaluated, only 2 have been identified that exhibit minimal to no susceptibility to hCGβcf.

scholarly journals Falsely Decreased Human Chorionic Gonadotropin (hCG) Results Due to Increased Concentrations of the Free β Subunit and the β Core Fragment in Quantitative hCG Assays

2010 ◽  
Vol 56 (12) ◽  
pp. 1839-1844 ◽  
Author(s):  
David G Grenache ◽  
Dina N Greene ◽  
Anand S Dighe ◽  
Corinne R Fantz ◽  
Daniel Hoefner ◽  
...  
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
False Negative ◽  
Normal Pregnancy ◽  
Serum Samples ◽  
Core Fragment ◽  
Negative Results ◽  
Fixed Concentration ◽  
False Negative Results ◽  
High Concentrations

BACKGROUND Earlier studies have shown that increased concentrations of certain human chorionic gonadotropin (hCG) variants can cause false-negative results in some qualitative hCG devices. The objective of this study was to determine if increased concentrations of hCGβ and hCGβ core fragment (hCGβcf) cause falsely decreased results on 9 commercially available quantitative hCG assays. METHODS Several concentrations of purified hCGβ and hCGβcf were added to 2 sets of 6 serum samples with and without a fixed concentration of intact hCG. We examined 9 widely used immunoassays to measure immunoreactive hCG. Falsely decreased results were defined as those in which the measured hCG concentration was ≤50% of expected. RESULTS High concentrations of hCGβ (≥240 000 pmol/L) produced falsely decreased hCG measurements in 2 assays known to detect this variant. Similarly, high concentrations of hCGβcf (≥63 000 pmol/L) produced falsely decreased hCG measurements in 3 assays that do not detect purified hCGβcf. Two assays were identified that detected both hCGβ and hCGβcf, and neither produced falsely decreased results in the presence of high concentrations of these variants. CONCLUSIONS Extremely high concentrations of hCG variants can cause falsely decreased results in certain quantitative hCG assays. Of the 9 assays examined, none exhibited falsely decreased results in the presence of hCGβ concentrations typically associated with hCGβ-producing malignancies. Two assays exhibited decreased (>50%) hCG results in the presence of hCGβcf concentrations found during normal pregnancy.

scholarly journals Analytical and Clinical Evaluation of the NOWDiagnostics ADEXUSDx Human Chorionic Gonadotropin Test Using Whole Blood

2016 ◽  
Vol 1 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Robert D Nerenz ◽  
Jennifer R Bell ◽  
Nancy Montes de Oca ◽  
Joann Short ◽  
Theresa Mims ◽  
...  
Keyword(s):  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Whole Blood ◽  
Point Of Care ◽  
False Negative ◽  
Sample Volume ◽  
High Dose ◽  
Control Line ◽  
Intermediate Range ◽  
Pregnancy Status

Abstract Background Point-of-care (POC) urine qualitative human chorionic gonadotropin (hCG) devices are used to rapidly assess pregnancy status, but many of these devices are susceptible to false-negative results caused by increased concentrations of hCG β core fragment (hCGβcf) that does not contain hCGβcf. Methods Purified hCG was added to hCG-negative heparinized whole blood to generate samples with known hCG concentrations, and the resulting samples were used to evaluate device sensitivity, low-end reproducibility, high-dose hook effect, intermediate range performance, acceptable sample volume, acceptable hematocrit range, and lot-to-lot variation. Device performance was also prospectively evaluated in 40 pregnant and 40 nonpregnant women aged 18–44 years in a hospital-based clinic or an academic hospital emergency department. Results All device observations were positive using a whole blood sample containing a plasma hCG concentration of 2.2 × 106 IU/L, and all device observations were positive from18 IU/L to 1.2 × 103 IU/L and from 2.5 × 104 IU/L to 2.2 × 106 IU/L. Three invalid results were observed in the intermediate range because of decreased control line intensity. The minimum sample volume was 30 μL, and maximum hematocrit was 46%. In 40 pregnant and 40 nonpregnant women aged 18–44 years, the device generated 100% concordance with urine qualitative and plasma quantitative test results. Conclusions The ADEXUSDx™ hCG test demonstrates acceptable performance for the determination of pregnancy status using capillary fingerstick samples.

scholarly journals Multiplex Target-Redundant RT-LAMP for Robust Detection of SARS-CoV-2 Using Fluorescent Universal Displacement Probes

2021 ◽  
Author(s):  
Enos C Kline ◽  
Nuttada Panpradist ◽  
Ian T Hull ◽  
Qin Wang ◽  
Amy K Oreskovic ◽  
...  
Keyword(s):  
Molecular Diagnostics ◽  
Detection System ◽  
Point Of Care ◽  
False Negative ◽  
Cost Effective ◽  
Internal Amplification Control ◽  
Robust Detection ◽  
Negative Results ◽  
False Negative Results ◽  
Target Redundancy

AbstractThe increasing prevalence of variant lineages during the COVID-19 pandemic has the potential to disrupt molecular diagnostics due to mismatches between primers and variant templates. Point-of-care molecular diagnostics, which often lack the complete functionality of their high throughput laboratory counterparts, are particularly susceptible to this type of disruption, which can result in false negative results. To address this challenge, we have developed a robust Loop Mediated Isothermal Amplification assay with single tube multiplexed multi-target redundancy and an internal amplification control. A convenient and cost-effective target specific fluorescence detection system allows amplifications to be grouped by signal using adaptable probes for pooled reporting of SARS-COV-2 target amplifications or differentiation of the Internal Amplification Control. Over the course of the pandemic, primer coverage of viral lineages by the three redundant sub-assays has varied from assay to assay as they have diverged from the Wuhan-Hu-1 isolate sequence, but aggregate coverage has remained high for all variant sequences analyzed, with a minimum of 97.4% (Variant of Interest: Eta). In three instances (Delta, Gamma, Eta), a high frequency mismatch with one of the three sub-assays was observed, but overall coverage remained high due to multi-target redundancy. When challenged with extracted human samples the multiplexed assay showed 100% sensitivity for samples containing greater than 30 copies of viral RNA per reaction, and 100% specificity. These results are further evidence that conventional laboratory methodologies can be leveraged at the point-of-care for robust performance and diagnostic stability over time.

scholarly journals Significance of pregnancy test false negative results due to elevated levels of β-core fragment hCG

2017 ◽  
Vol 38 (4) ◽  
pp. 449-455 ◽  
Author(s):  
Sarah Johnson ◽  
Saji Eapen ◽  
Peter Smith ◽  
Graham Warren ◽  
Michael Zinaman
Keyword(s):  
False Negative ◽  
Pregnancy Test ◽  
Core Fragment ◽  
Negative Results ◽  
False Negative Results

scholarly journals Performance of SARS-CoV-2 antigen testing in symptomatic and asymptomatic adults: a single-center evaluation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Stephanie L. Mitchell ◽  
Steven Orris ◽  
Tanner Freeman ◽  
Megan C. Freeman ◽  
Michelle Adam ◽  
...  
Keyword(s):  
Symptom Onset ◽  
Point Of Care ◽  
False Negative ◽  
Poor Performance ◽  
Nasopharyngeal Swab ◽  
Lower Sensitivity ◽  
Negative Results ◽  
Asymptomatic Patients ◽  
False Negative Results ◽  
Antigen Testing

Abstract Background Antigen testing offers rapid and inexpensive testing for SARS-CoV-2 but concerns regarding performance, especially sensitivity, remain. Limited data exists for use of antigen testing in asymptomatic patients; thus, performance and reliability of antigen testing remains unclear. Methods 148 symptomatic and 144 asymptomatic adults were included. A nasal swab was collected for testing by Quidel Sofia SARS IFA (Sofia) as point of care. A nasopharyngeal swab was also collected and transported to the laboratory for testing by Cepheid Xpert Xpress SARS-CoV-2/Flu/RSV RT-PCR (Cepheid). Results Overall, Sofia had good agreement with Cepheid (> 95%) in adults, however was less sensitive. Sofia had a sensitivity of 87.8% and 33.3% for symptomatic and asymptomatic patients, respectively. Among symptomatic patients, testing > 5 days post symptom onset resulted in lower sensitivity (82%) when compared with testing within 5 days of symptom onset (90%). Of the four Sofia false-negative results in the asymptomatic cohort, 50% went on to develop COVID-19 disease within 5 days of testing. Specificity in both symptomatic and asymptomatic cohorts was 100%. Conclusions Sofia has acceptable performance in symptomatic adults when tested < 5 days of symptom onset. Caution should be taken when testing patients with ≥ 5 days of symptoms. The combination of low prevalence and reduced sensitivity results in relatively poor performance of in asymptomatic patients. NAAT-based diagnostic assays should be considered in when antigen testing is unreliable, particularly in symptomatic patients with > 5 days of symptom onset and asymptomatic patients.

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