Crowded Probabilities in Tests for the Presence of Infection

In the presentation, problems have been addressed in perception and popular delusions in the interpretation of information related to the level of confidence / uncertainty of tests by which the presence or absence of contamination is verified. The theoretical essence of the probabilities of a false positive and false negative result, as well as the level of confidence / uncertainty of the test results and on this basis there are assumptions about the perception of such information and possible misconceptions in its interpretation by society. Assumptions made are checked on the information based on a non-reporting survey. The results obtained reveal user difficulties in rationalizing and interpreting the data provided as well as when detecting logical links characteristic of such information.

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RISK FACTORS FOR FALSE-POSITIVE AND FALSE-NEGATIVE FECAL IMMUNOCHEMICAL TEST RESULTS IN COLORECTAL CANCER SCREENING: SYSTEMATIC REVIEW AND META-ANALYSIS

10.1055/s-0038-1637308 ◽

2018 ◽

Author(s):

CM de Klerk ◽

LM Vendrig ◽

PM Bossuyt ◽

E Dekker

Keyword(s):

Colorectal Cancer ◽

Risk Factors ◽

Systematic Review ◽

Cancer Screening ◽

Colorectal Cancer Screening ◽

False Positive ◽

Meta Analysis ◽

False Negative ◽

Test Results ◽

Immunochemical Test

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Three Years of Experience With Random Urinary Homovanillic and Vanillylmandelic Acid Levels in the Diagnosis of Neuroblastoma

PEDIATRICS ◽

10.1542/peds.79.2.203 ◽

1987 ◽

Vol 79 (2) ◽

pp. 203-205

Author(s):

Mendel Tuchman ◽

Margaret L. R. Ramnaraine ◽

William G. Woods ◽

William Krivit

Keyword(s):

False Positive ◽

Homovanillic Acid ◽

False Negative ◽

False Negative Rate ◽

Urine Samples ◽

Vanillylmandelic Acid ◽

Test Results ◽

Upper Limit ◽

Positive Results ◽

Rule Out

During the last 3 years, random urine samples from 408 patients were tested for elevated homovanillic acid (HVA) and vanillylmandelic acid (VMA) levels to rule out the diagnosis of neuroblastoma. Thirty-seven of these patients had elevated HVA and/or VMA levels, and neuroblastoma was subsequently diagnosed. In three additional patients with negative test results (normal HVA and VMA levels), tumors were subsequently diagnosed (false-negative rate of 7.5%). Ten percent of the patients with neuroblastoma had normal HVA and 27.5% had normal VMA levels at the time of diagnosis. Only one patient (2.5%) with neuroblastoma had elevated VMA levels in the presence of normal HVA levels. More than 60% of the patients with neuroblastoma had urinary HVA and/or VMA levels higher than twice the upper limit of normal. No false-positive results were encountered. Age and stage distributions of the patients are shown, and the significance of the results is discussed.

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Multivariate interpretation of laboratory tests used in monitoring patients

Clinical Chemistry ◽

10.1093/clinchem/36.5.748 ◽

1990 ◽

Vol 36 (5) ◽

pp. 748-751 ◽

Cited By ~ 2

Author(s):

H B Slotnick ◽

P Etzell

Keyword(s):

Small Groups ◽

False Positive ◽

Laboratory Tests ◽

False Negative ◽

Test Results ◽

Laboratory Findings ◽

Bonferroni Inequality ◽

The Impact

Abstract This study demonstrates an approach to the problem of minimizing false-negative and false-positive laboratory findings. In this approach, we consider the fact that results of laboratory tests are correlated, utilize within-person test results to interpret current results, and minimize the impact of multivariate conservatism by examining test results in small groups. The procedure requires panels of tests to be divided into related subpanels, testing each subpanel independently, and using the Bonferroni inequality to determine whether any of the observed values for a given subpanel is "out-of-range." The procedure is demonstrated, and its limitations are observed and discussed.

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False positive antigen test for Dirofilaria immitis after heat treatment of the blood sample in a microfilaremic dog infected with Acanthocheilonema dracunculoides

Parasites & Vectors ◽

10.1186/s13071-020-04376-9 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Viktor Szatmári ◽

Martin Willem van Leeuwen ◽

Christine Jantine Piek ◽

Luigi Venco

Keyword(s):

Heat Treatment ◽

Blood Sample ◽

Real Time ◽

Real Time Pcr ◽

False Positive ◽

Dirofilaria Immitis ◽

False Negative ◽

Correct Identification ◽

Test Results ◽

Antigen Test

Abstract Background Dirofilaria immitis is responsible for heartworm disease in dogs in endemic areas worldwide. Screening for this infection is done by blood tests. Antigen testing is the most sensitive method to detect an infection with adult (female) worms. Microscopic examination of a blood smear or Knott’s test can be used to detect circulating microfilariae, the infective larvae. To increase the sensitivity of the antigen test by decreasing the false negative test results, heating of the blood sample has been recommended in recent guidelines. Heating is believed to remove blocking immune-complexes. Circulating microfilariae are not specific findings for heartworm infection, as other nematodes (among others, Acanthocheilonema dracunculoides) can also result in microfilaremia. Although the type of microfilariae cannot be determined by microscopy alone, real-time PCR can reliably identify the infecting nematode species. Correct identification of the parasite is of major importance, as an infection with D. immitis requires antiparasitic therapy, whereas A. dracunculoides is thought to be a clinically irrelevant coincidental finding. The present case report describes a microfilaremic dog where the initial antigen test for D. immitis turned positive after heat treatment, whereas real-time PCR revealed that the microfilariae were A. dracunculoides (syn. Dipetalonema dracunculoides). Results A circa 5-year old, asymptomatic Spanish mastiff dog was referred for heartworm therapy because microfilariae were found via a screening blood test. The dog was recently imported to the Netherlands from Spain, where it had been a stray dog. Antigen tests on a plasma sample for D. immitis were performed with three different test kits, which all turned out to be negative. However, heat treatment of two of these samples were carried out and both of them led to a positive antigen test result. Real-time PCR showed that the circulating microfilariae belonged to A. dracunculoides species. Three administrations of moxidectin spot-on at monthly intervals resulted in a negative antigen and a negative Knott’s tests one month after the last treatment. Conclusions We conclude that heat treatment of initially negative blood samples for D. immitis could lead to false positive antigen test results if the dog is infected with A. dracunculoides.

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The Dangers of False-Positive and False-Negative Test Results: False-Positive Results as a Function of Pretest Probability

Clinics in Laboratory Medicine ◽

10.1016/j.cll.2007.12.009 ◽

2008 ◽

Vol 28 (2) ◽

pp. 305-319 ◽

Cited By ~ 14

Author(s):

Brian R. Jackson

Keyword(s):

False Positive ◽

False Negative ◽

Pretest Probability ◽

Test Results ◽

Negative Test ◽

Positive Results ◽

False Negative Test

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The Lifetime Economic Burden of Inaccurate HER2 Testing: Estimating the Costs of False-Positive and False-Negative HER2 Test Results in US Patients with Early-Stage Breast Cancer

Value in Health ◽

10.1016/j.jval.2015.01.012 ◽

2015 ◽

Vol 18 (4) ◽

pp. 541-546 ◽

Cited By ~ 13

Author(s):

Louis P. Garrison ◽

Joseph B. Babigumira ◽

Anthony Masaquel ◽

Bruce C.M. Wang ◽

Deepa Lalla ◽

...

Keyword(s):

Breast Cancer ◽

Economic Burden ◽

False Positive ◽

Early Stage ◽

False Negative ◽

Early Stage Breast Cancer ◽

Test Results ◽

Her2 Testing

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False Covid-19 Test Results – Could We Do Things Better? A Personal Opinion

Asian Journal of Pharmacy Nursing and Medical Sciences ◽

10.24203/ajpnms.v8i5.6349 ◽

2020 ◽

Vol 8 (5) ◽

Author(s):

Suzanne Lisbeth Ekelund

Keyword(s):

False Positive ◽

False Negative ◽

Test Results ◽

Negative Results ◽

False Negative Results ◽

Personal Opinion ◽

Potential Problems

This paper describes the problems with false covid-19 test results, both false positive and false negative results. The problems are related to the quality of tests, test sampling and the currently limited follow-up procedures. A test and follow-up strategy that could decrease the potential problems is suggested.

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Comparison of Accuracy in Expert Clinical Examination versus Magnetic Resonance Imaging and Arthroscopic Exam in Diagnosis of Meniscal Tear

Advances in Orthopedics ◽

10.1155/2020/1895852 ◽

2020 ◽

Vol 2020 ◽

pp. 1-5

Author(s):

Seyed Ali Hashemi ◽

Mohammad Reza Ranjbar ◽

Mohammad Tahami ◽

Reza Shahriarirad ◽

Amirhossein Erfani

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Clinical Examination ◽

False Positive ◽

Statistical Significance ◽

False Negative ◽

Test Results ◽

Meniscal Tears ◽

Resonance Imaging ◽

Presenting Symptoms

Background. Many clinical tests and diagnostic studies have been developed to increase the clinician’s ability to accurately diagnose disorders of the knee. Torn menisci or ligamentous structures within the knee cause significant pain and disability and thus require expeditious management. This study was conducted to evaluate the accuracy of clinical examination in comparison with MRI examination and with the help of arthroscopic examination as the gold standard in the diagnosis of meniscal tears. Method. All of the arthroscopic surgery candidates, presenting symptoms of meniscal or cruciate ligament lesions, referring to Namazi and Chamran hospitals, Shiraz, Iran, were included in this study. Clinical examination (including McMurray test, Apley test, and 20 Thessaly test) was performed before the arthroscopy, and the results were recorded in special forms. Magnetic resonance imaging (MRI) results were also added. Then, arthroscopy was performed, declaring the definite diagnosis, and the results were compared to the results obtained from both tests and MRI. Statistical analysis was performed using SPSS software. Results. 86 patients with a mean age of 27 years old, including 63 (73%) male and 23 (27%) female, were studied. 57 (66%), 19 (22%), and 10 (12%) injuries were caused by sports, twisting, or trauma, respectively. Arthroscopic results showed 32 meniscal tears, of which 28 (87%) and 4 (13%) were in medial and lateral menisci, respectively, including 10 bucket handle, 17 longitudinal, and 5 of other types (transverse, oblique, radial) of injuries. Comparing MRI results to arthroscopic results, we had 2 false-positive and 2 false-negative cases. 62 cases of McMurray test results were accurate; 15 and 9 cases were reported false positive and false negative, respectively. 60 cases of Apley test results were accurate; 16 and 10 cases were reported false positive and false negative, respectively. 78 cases of Thessaly test results were accurate; 5 and 3 cases were reported false positive and false negative, respectively. Comparing Thessaly test results to McMurray and Apley showed statistical significance (P<0.05). Comparing Thessaly test results to MRI showed no statistical significance (P=0.151), while comparing McMurray and Apley test results to MRI showed statistical significance (P<0.01). Conclusion. Clinical examination, performed by an experienced examiner, can have equal or even more diagnostic accuracy compared to MRI to evaluate meniscal lesions. In this study, the Thessaly test has been approved as a reliable clinical test in the diagnosis of meniscal tears.

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