‘False-positive’ and ‘false-negative’ test results in clinical urine drug testing

Bioanalysis ◽  
2009 ◽  
Vol 1 (5) ◽  
pp. 937-952 ◽  
Author(s):  
Gary M Reisfield ◽  
Bruce A Goldberger ◽  
Roger L Bertholf
Keyword(s):  
False Positive ◽  
Drug Testing ◽  
False Negative ◽  
Test Results ◽  
Negative Test ◽  
Urine Drug Testing ◽  
Urine Drug ◽  
False Negative Test

scholarly journals Lower Cutoffs for LC-MS/MS Urine Drug Testing Indicates Better Patient Compliance

2017 ◽  
Vol 7 (20;7) ◽  
pp. E1107-E1113
Author(s):  
Kevin Krock
Keyword(s):  
Health Care Providers ◽  
Drug Testing ◽  
Illicit Drugs ◽  
Patient Adherence ◽  
False Negative ◽  
Test Results ◽  
Care Providers ◽  
Urine Drug Testing ◽  
Urine Drug ◽  
Cutoff Levels

Background: Urine drug testing is used by health care providers to determine a patient’s compliance to their prescribed regimen and to detect non-prescribed medications and illicit drugs. However, the cutoff levels used by clinical labs are often arbitrarily set and may not reflect the urine drug concentrations of compliant patients. Objectives: Our aim was to test the hypothesis that commonly used cutoffs for many prescribed and illicit drugs were set too high, and methods using these cutoffs may yield a considerable number of false-negative results. The goals of this study were to outline the way to analyze patient results and estimate a more appropriate cutoff, develop and validate a high sensitivity analytical method capable of quantitating drugs and metabolites at lower than the commonly used cutoffs, and determine the number of true positive results that would have been missed when using the common cutoffs. Study Design: This was a retrospective study of urine specimens submitted for urine drug testing as part of the monitoring of prescription drug compliance described in chronic opioid therapy treatment guidelines. Setting: The study was set in a clinical toxicology laboratory, using specimens submitted for routine analysis by health care providers in the normal course of business. Methods: Lognormal distributions of test results were generated and fitted with a trendline to estimate the required cutoff level necessary to capture the normal distributions of each drug for the patient population study. A validated laboratory derived liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis capable of achieving the required cutoff levels was developed for each drug and/or metabolite. Results: The study shows that a lognormal distribution of patient urine test results fitted with a trendline is appropriate for estimating the required cutoff levels needed to assess medication adherence. The study showed a wide variation in the false-negative rate, ranging from 1.5% to 94.3% across a range of prescribed and illicit drugs. Limitations: The patient specimens were largely sourced from patients in either a long-term pain management program or in treatment for substance use disorder in the US. These specimens may not be representative of patients in other types of treatment or in countries with different approaches to these issues. Conclusions: The high-sensitivity method reduces false-negative results which could negatively impact patient care. Clinicians using less sensitive methods for detecting and quantifying drugs and metabolites in urine should exercise caution in assessing patient adherence using and changing the treatment plan based on those results. Key words: Urine drug testing, patient adherence, clinical toxicology, immunoassay, LC-MS, definitive drug testing, REMS, negative test results, false negative

Risk factors for false positive and for false negative test results in screening with fecal occult blood testing

2013 ◽  
Vol 133 (10) ◽  
pp. 2408-2414 ◽  
Author(s):  
Inge Stegeman ◽  
Thomas R. de Wijkerslooth ◽  
Esther M. Stoop ◽  
Monique van Leerdam ◽  
M. van Ballegooijen ◽  
...  
Keyword(s):  
Risk Factors ◽  
False Positive ◽  
False Negative ◽  
Occult Blood ◽  
Fecal Occult Blood Testing ◽  
Fecal Occult Blood ◽  
Test Results ◽  
Negative Test ◽  
Fecal Occult ◽  
False Negative Test

scholarly journals Informed choice on Pap smear still limited by lack of knowledge on the meaning of false-positive or false-negative test results

2011 ◽  
Vol 85 (2) ◽  
pp. 214-218 ◽  
Author(s):  
Ida J. Korfage ◽  
Marjolein van Ballegooijen ◽  
Brendy Wauben ◽  
J. Dik F. Habbema ◽  
Marie-Louise Essink-Bot
Keyword(s):  
False Positive ◽  
Pap Smear ◽  
False Negative ◽  
Informed Choice ◽  
Test Results ◽  
Negative Test ◽  
False Negative Test ◽  
Lack Of Knowledge

Incidence and Recovery of Salmonellae and Other Bacteria from Commercially Processed Poultry Carcasses at Selected Pre- and Post-Evisceration Steps

1989 ◽  
Vol 52 (2) ◽  
pp. 88-91 ◽  
Author(s):  
H. S. LILLARD
Keyword(s):  
False Negative ◽  
Aerobic Bacteria ◽  
Processing Plant ◽  
Test Results ◽  
Negative Test ◽  
Commercial Plant ◽  
Sampling Points ◽  
Processing Line ◽  
False Negative Test ◽  
Progressive Sampling

This study was undertaken to determine whether bacteria are already attached to poultry skin when birds arrive at the processing plant. Multiple rinses were performed on breast skin and whole carcasses taken from five processing points in a commercial plant: Before scalding, after scalding, after picking, after the final washer, and from the exit end of the chiller. Aerobic bacteria and Enterobacteriaceae were recovered from carcasses in up to 40 consecutive whole carcass rinses with a difference of only about one log for Enterobacteriaceae, and 1 to 2 logs for aerobes from the first to the last rinse of carcasses taken from the beginning and the end of the processing line. Data from rinses prior to scalding indicated that bacteria were firmly attached to poultry carcasses when they first arrived in the plant. Not all bacteria were removed during processing; however, there were fewer aerobes and Enterobacteriaceae at progressive sampling points. Attached salmonellae were not always recovered in the first whole carcass rinse, but were sometimes recovered in 3rd, 5th, and 10th rinses. These data show that a single whole carcass rinse can result in false negative test results for salmonellae. Because of the small number of positive samples in this study, the probability of recovering salmonellae with a single whole carcass rinse could not be estimated accurately.

Financial viability of screening for drugs of abuse

1995 ◽  
Vol 41 (5) ◽  
pp. 805-808 ◽  
Author(s):  
M A Peat
Keyword(s):  
Drug Testing ◽  
Drugs Of Abuse ◽  
The United States ◽  
Economic Benefits ◽  
Postal Service ◽  
Test Results ◽  
United States Postal Service ◽  
Financial Benefits ◽  
Urine Drug Testing ◽  
Urine Drug

Abstract Urine drug testing is now a common practice in the American workplace; a recent survey indicated that > 90% of companies with > 5000 employees have some type of testing program. These programs have indeed reduced the rate of drug-positive test results; for example, recent data from the Federal Aviation Agency show that the rate for 1993 was 0.82% compared with 0.95% for 1992. Many corporations have stated that urine drug testing, as a component of a substance abuse policy, results in significant savings, e.g., from decreased absenteeism and turnover. The United States Postal Service recently completed a longitudinal study on the economic benefits and found that, over the average tenure of an annual intake of employees, there were savings of more than $100 million. Although this study clearly demonstrates the financial benefits of preemployment drug testing, the decision to test is not based solely on this but also on the regulatory environment and on the potential impact of a major accident attributable to the use of drugs or alcohol in the workplace.

scholarly journals Estimating the false-negative test probability of SARS-CoV-2 by RT-PCR

2020 ◽  
Vol 25 (50) ◽  
Author(s):  
Paul S Wikramaratna ◽  
Robert S Paton ◽  
Mahan Ghafari ◽  
José Lourenço
Keyword(s):  
Symptom Onset ◽  
False Positive ◽  
False Negative ◽  
Positive Test ◽  
Rt Pcr ◽  
Negative Test ◽  
False Positive Test ◽  
True Number ◽  
Test Probability ◽  
False Negative Test

Background Reverse-transcription PCR (RT-PCR) assays are used to test for infection with the SARS-CoV-2 virus. RT-PCR tests are highly specific and the probability of false positives is low, but false negatives are possible depending on swab type and time since symptom onset. Aim To determine how the probability of obtaining a false-negative test in infected patients is affected by time since symptom onset and swab type. Methods We used generalised additive mixed models to analyse publicly available data from patients who received multiple RT-PCR tests and were identified as SARS-CoV-2 positive at least once. Results The probability of a positive test decreased with time since symptom onset, with oropharyngeal (OP) samples less likely to yield a positive result than nasopharyngeal (NP) samples. The probability of incorrectly identifying an uninfected individual due to a false-negative test was considerably reduced if negative tests were repeated 24 hours later. For a small false-positive test probability (<0.5%), the true number of infected individuals was larger than the number of positive tests. For a higher false-positive test probability, the true number of infected individuals was smaller than the number of positive tests. Conclusion NP samples are more sensitive than OP samples. The later an infected individual is tested after symptom onset, the less likely they are to test positive. This has implications for identifying infected patients, contact tracing and discharging convalescing patients who are potentially still infectious.

scholarly journals False-negative test results to non-agglutinating (incomplete) antibodies.

1982 ◽  
Vol 58 (4) ◽  
pp. 275-276
Author(s):  
E de Klerk ◽  
C A Sharp ◽  
C Geffen ◽  
R Anderson
Keyword(s):  
False Negative ◽  
Test Results ◽  
Negative Test ◽  
False Negative Test

scholarly journals COVID-19 Testing: Challenges, Limitations and Suggestions for Improvement

2020 ◽  
Author(s):  
Emily Hu
Keyword(s):  
False Negative ◽  
Diagnostic Methods ◽  
Test Results ◽  
Successful Management ◽  
Negative Test ◽  
Reliable Methods ◽  
False Negative Test

Reliable methods to confirm the diagnosis of COVID-19 are essential to the successful management and containment of the virus. Current diagnostic options are limited in type, supply, and reliability. This article explores the controversial unreliability of existing diagnostic methods and maintains that more reliable diagnostic methods, combinations, and sequencing are necessary to effectively assist in reducing the occurrence of discharge of the patient on false negative test results. This reduction would in effect reduce transmission of the disease.

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