scholarly journals New Meconium Biomarkers of Prenatal Methamphetamine Exposure Increase Identification of Affected Neonates

2010 ◽  
Vol 56 (5) ◽  
pp. 856-860 ◽  
Author(s):  
Teresa R Gray ◽  
Tamsin Kelly ◽  
Linda L LaGasse ◽  
Lynne M Smith ◽  
Chris Derauf ◽  
...  
Keyword(s):  
False Negative ◽  
Screening Tests ◽  
Test Results ◽  
Third Trimester ◽  
Self Reports ◽  
Liquid Chromatography Tandem Mass ◽  
Tandem Mass Spectrometric ◽  
New Biomarkers ◽  
Related Compounds ◽  
Positive Results

Abstract Background: Prenatal methamphetamine (MAMP) exposure is poorly reflected in neonatal meconium. Often, maternal self-reported MAMP use is not corroborated by positive results in amphetamines immunoassays of meconium, and even if initial test results are positive, they frequently are not confirmed for MAMP or amphetamine (AMP) by chromatographic analysis. The presence of the MAMP metabolites p-hydroxymethamphetamine (pOHMAMP), p-hydroxyamphetamine (pOHAMP), and norephedrine (NOREPH) in meconium may improve the identification of MAMP- and AMP-exposed neonates. Methods: Immunoassay-positive and -negative meconium samples were subjected to liquid chromatography– tandem mass spectrometric reanalysis for these recently identified metabolites. Results: pOHAMP and NOREPH were detected only when MAMP and/or AMP were present and thus do not appear to be promising biomarkers of prenatal MAMP exposure. pOHMAMP, in contrast, identified 6 additional neonates whose mothers reported MAMP exposure, yet had a meconium sample screened as negative; pOHMAMP was more likely to be present if maternal MAMP use continued into the third trimester. Although the pOHMAMP results for meconium samples corroborated the maternal self-reports, the confirmation rate for positive meconium screening results did not improve with the inclusion of these new biomarkers. Conclusions: pOHMAMP identified additional MAMP- exposed neonates; therefore, MAMP, AMP, and pOHMAMP should be included in meconium chromatographic analyses. Maximizing the identification of MAMP-exposed children requires improvement in immunoassay screening tests to reduce false-negative and false-positive results. Additional research will help clarify which AMP-related compounds, if any, contribute to unconfirmed positive results in screening tests. Furthermore, nonamphetamine compounds endogenous to the complex meconium matrix also may cross-react, making chromatographic confirmation of screening results essential.

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

PEDIATRICS ◽  
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.

scholarly journals Biosensor Analysis of β-Lactams in Milk Using the Carboxypeptidase Activity of a Bacterial Penicillin Binding Protein

2006 ◽  
Vol 89 (3) ◽  
pp. 832-837 ◽  
Author(s):  
Åse SternesjÖ ◽  
Eva Gustavsson
Keyword(s):  
False Positive ◽  
Polyclonal Antibodies ◽  
Active Form ◽  
False Negative ◽  
Screening Tests ◽  
Receptor Protein ◽  
Penicillin G ◽  
Penicillin Binding Protein ◽  
Spr Biosensor ◽  
Positive Results

Abstract The applicability of a -lactam receptor protein for detection of β-lactam antibiotics in milk using surface plasmon resonance (SPR) biosensor technology was investigated. The advantage of using a receptor protein instead of antibodies for detection of β-lactams is that a generic assay, specific for the active form of the β-lactam structure, is obtained. Two assays based on the enzymatic activity of the dd-carboxypeptidase from Actinomadura R39 were developed, using a Biacore SPR biosensor. The carboxypeptidase converts a tri-peptide into a di-peptide, a reaction which is inhibited in the presence of β-lactams. Polyclonal antibodies against the 2 peptides were developed and used to measure the amount of enzymatic product formed (di-peptide assay) or the amount of remaining enzymatic substrate (tri-peptide assay), respectively. The 2 assays showed similar performances with respect to detection limits (1.2 and 1.5 μg/kg, respectively) and precision (coefficient of variation <5%) for penicillin G in milk. Several other β-lactams were detected at or near their respective maximum residue limit. Furthermore, the 2 peptide assays were evaluated against 5 commercial kit tests in the screening of 195 producer milk samples. The biosensor assays showed 0% false-negative and 27% false-positive results, whereas the figures were 0% false-negative and 2753% false-positive results for other screening tests investigated.

scholarly journals Effect of urine adulterants on commercial drug abuse screening test strip results

2020 ◽  
Vol 71 (1) ◽  
pp. 87-93
Author(s):  
Ivana Rajšić ◽  
Dragana Javorac ◽  
Simona Tatović ◽  
Aleksandra Repić ◽  
Danijela Đukić-Ćosić ◽  
...  
Keyword(s):  
Drug Abuse ◽  
False Negative ◽  
Test Strip ◽  
Lemon Juice ◽  
Screening Tests ◽  
Urine Specimen ◽  
Test Results ◽  
Negative Results ◽  
Urine Drug ◽  
Validity Tests

AbstractImmunochromatographic strips for urine drug screening tests (UDSTs) are common and very suitable for drug abuse monitoring, but are also highly susceptible to adulterants kept in the household, which can significantly alter test results. The aim of this study was to see how some of these common adulterants affect UDST results in practice and whether they can be detected by sample validity tests with pH and URIT 11G test strips. To this end we added household chemicals (acids, alkalis, oxidizing agents, surfactants, and miscellaneous substances) to urine samples positive for amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), tetrahydrocannabinol, heroin, cocaine, or benzodiazepines (diazepam or alprazolam) and tested them with one-component immunochromatographic UDST strips. The UDST for cocaine resisted adulteration the most, while the cannabis test produced the most false negative results. The most potent adulterant that barely changed the physiological properties of urine specimens and therefore escaped adulteration detection was vinegar. Besides lemon juice, it produced the most false negative test results. In conclusion, some urine adulterants, such as vinegar, could pass urine specimen validity test and remain undetected by laboratory testing. Our findings raise concern about this issue of preventing urine tampering and call for better control at sampling, privacy concerns notwithstanding, and better sample validity tests.

scholarly journals A 2-Gene Host Signature for Improved Accuracy of COVID-19 Diagnosis Agnostic to Viral Variants

2022 ◽  
Author(s):  
Jack Albright ◽  
Eran Mick ◽  
Estella Sanchez-Guerrero ◽  
Jack Kamm ◽  
Anthea Mitchell ◽  
...  
Keyword(s):  
Characteristic Curve ◽  
False Negative ◽  
Support Vector ◽  
Nasopharyngeal Swab ◽  
Test Results ◽  
Rna Seq ◽  
Respiratory Illnesses ◽  
Improving Accuracy ◽  
Improved Accuracy ◽  
Positive Results

The continued emergence of SARS-CoV-2 variants is one of several factors that may cause false negative viral PCR test results. Such tests are also susceptible to false positive results due to trace contamination from high viral titer samples. Host immune response markers provide an orthogonal indication of infection that can mitigate these concerns when combined with direct viral detection. Here, we leverage nasopharyngeal swab RNA-seq data from patients with COVID-19, other viral acute respiratory illnesses and non-viral conditions (n=318) to develop support vector machine classifiers that rely on a parsimonious 2-gene host signature to predict COVID-19. Optimal classifiers achieve an area under the receiver operating characteristic curve (AUC) greater than 0.9 when evaluated on an independent RNA-seq cohort (n=553). We show that a classifier relying on a single interferon-stimulated gene, such as IFI6 or IFI44, measured in RT-qPCR assays (n=144) achieves AUC values as high as 0.88. Addition of a second gene, such as GBP5, significantly improves the specificity compared to other respiratory viruses. The performance of a clinically practical 2-gene RT-qPCR classifier is robust across common SARS-CoV-2 variants, including Omicron, and is unaffected by cross-contamination, demonstrating its utility for improving accuracy of COVID-19 diagnostics.

scholarly journals Screening for non-communicable diseases

2020 ◽  
Vol 9 (3) ◽  
pp. 1092
Author(s):  
D. M. Christe ◽  
S. Vijaya ◽  
K. Tharangini
Keyword(s):  
Breast Cancer ◽  
Diabetes Mellitus ◽  
Cervical Cancer ◽  
Communicable Diseases ◽  
Screening Tests ◽  
Screening Methods ◽  
Care Hospital ◽  
Test Results ◽  
Non Communicable Diseases ◽  
Positive Results

Background: This study was conducted to enumerate the results of screening for non-communicable diseases in the NCD clinic over a period of one year in a tertiary health centre.Methods: The results from screening tests conducted in the NCD clinic, for detecting hypertension, diabetes mellitus, breast cancer and cervical cancer, in Government tertiary care Hospital for Women, Chennai, were recorded. The flowchart and screening methods followed were those recommended by the NHM - NPCDCS. Data thus obtained was analyzed using standard statistical methods.Results: Of 42,519 women screened for common non communicable diseases - hypertension, diabetes mellitus, breast cancer and cervical cancer, nearly 5.55% women (n = 2359) had positive results, for any one of the diseases screened. Of 11,708 women screened for diabetes mellitus and 13,971 screened for hypertension, positive results were found in 856 women and 1,216 women respectively. Around 7,568 women were screened for cervical cancer and 175 women tested positive. A large number of 9,272 women were screened for breast cancer and 112 women had positive results. As per the guidelines, women who tested positive for screening tests were referred to the concerned departments in RGGGH.Conclusions: Nearly 42,519 women were screened for common non-communicable diseases (NCDs) - hypertension, diabetes mellitus, breast cancer and cervical cancer, and 5.55% women had positive test results for any one of the diseases screened. The screening revealed, 8.7% of women had raised blood pressure, 7.31% had raised blood sugar levels, 1.21% women had positive screening test results for breast cancer, and 2.31% women for cervical cancer.

scholarly journals Diagnostic Considerations in the Measurement of Human Chorionic Gonadotropin in Aging Women

2005 ◽  
Vol 51 (10) ◽  
pp. 1830-1835 ◽  
Author(s):  
Jennifer A Snyder ◽  
Shannon Haymond ◽  
Curtis A Parvin ◽  
Ann M Gronowski ◽  
David G Grenache
Keyword(s):  
Older Women ◽  
Medical Intervention ◽  
Screening Tests ◽  
Test Results ◽  
Childbearing Age ◽  
Aging Women ◽  
Perimenopausal Women ◽  
History Of ◽  
Positive Results ◽  
Hcg Test

Abstract Background: Human chorionic gondadotropin (hCG) screening tests are performed on nearly all female patients of childbearing age before any medical intervention. Although older women usually have negative hCG test results, positive results do occur and may cause clinical confusion. We examined changes with age in serum hCG concentrations in nonpregnant women and investigated the use of serum follicle-stimulating hormone (FSH) measurements as an aid to interpreting higher than expected (“positive”) hCG results. Methods: We used 240 serum specimens for each of 4 female cohorts: pregnant, ≥18 years; nonpregnant, 18–40 years (premenopausal); nonpregnant, 41–55 years (perimenopausal); and nonpregnant, >55 years (postmenopausal). Patients were excluded if they had an ectopic pregnancy, a history of trophoblastic disease or a germ-cell tumor, or if no chart was available for review. Quantitative hCG and FSH tests were performed on each specimen. Results: Serum hCG concentrations in nonpregnant women increased with the age of the women. hCG results were higher and significantly different (P <0.0001) for nonpregnant women >55 years (<2.0 to 13.1 IU/L) compared with nonpregnant women 18–40 years (<2.0 to 4.6 IU/L) and 41–55 years (<2.0 to 7.7 IU/L). Nineteen nonpregnant women >40 years of age had hCG concentrations ≥5.0 IU/L, all with an FSH concentration >32.4 IU/L. The highest FSH concentration in pregnancy was 7.3 IU/L. Conclusions: Serum hCG increases with age in nonpregnant women. A cutoff of 14.0 IU/L should be used when interpreting hCG results in women >55 years of age. Pregnancy is unlikely in perimenopausal women 41–55 years of age with an hCG between 5.0 and 14.0 IU/L if serum FSH is >20.0 IU/L.

scholarly journals EDTA in Dried Blood Spots Leads to False Results in Neonatal Endocrinologic Screening

2008 ◽  
Vol 54 (3) ◽  
pp. 602-605 ◽  
Author(s):  
Ute Holtkamp ◽  
Jeanette Klein ◽  
Johannes Sander ◽  
Michael Peter ◽  
Nils Janzen ◽  
...  
Keyword(s):  
Newborn Screening ◽  
False Positive ◽  
Neonatal Screening ◽  
False Negative ◽  
Dried Blood Spots ◽  
Screening Tests ◽  
Blood Collection ◽  
Blood Spots ◽  
Sampling Procedures ◽  
Positive Results

Abstract Background: Blood samples for neonatal screening for inborn errors of metabolism are collected and shipped on standardized filter paper cards. Occasionally these samples are contaminated with EDTA, which is often used for anticoagulation. EDTA may interfere with newborn screening tests based on lanthanide fluorescence and thus lead to false-negative or false-positive results. Methods: We used tandem mass spectrometry (MS/MS) to detect EDTA in dried blood spots by use of an extra experiment that was integrated into the standard MS/MS neonatal screening and did not require an additional sample spot, nor extra time or work. We analyzed the influence of different blood sampling procedures on lanthanide fluorescence tests for thyroid-stimulating hormone (TSH) and 17-hydroxyprogesterone (17-OHP). Results: EDTA was increased in 138 of 190 000 newborn screening samples, 27 of which caused false- positive results in the immunoassay for 17-OHP. No false-negative TSH results were found. False-positive results in the 17-OHP test occurred when EDTA concentrations were >2.0 g/L; the TSH test, however, produced false negatives only when EDTA concentrations were >3.0 g/L. Using EDTA-containing devices the procedure of blood collection significantly influenced the concentration of the anticoagulant. Conclusion: Addition of EDTA quantification into standard MS/MS tests is a simple and useful method to avoid false-positive or false-negative neonatal screening results in lanthanide fluorescence–based tests.

Laboratory Testing Strategies

2017 ◽  
Author(s):  
Thomas P. Young
Keyword(s):  
Clinical Judgment ◽  
False Negative ◽  
Preliminary Test ◽  
Test Results ◽  
Testing Strategies ◽  
Laboratory Confirmation ◽  
Health Fairs ◽  
Hiv Antibodies ◽  
Positive Results

Laboratory confirmation of HIV infection is primarily through the detection of HIV antibodies in an individual. Using the current immunoassays and confirmatory testing, false-positive results are exceedingly rare. However, providers should use clinical judgment when interpreting test results and consider additional follow-up testing when appropriate. False-negative immunoassays are also exceedingly rare except for individuals who are early in their infection and have yet to produce HIV antibodies that are detectable by current assays. Rapid HIV tests have similar testing accuracies as compared to those of currently available immunoassays and can be useful testing options for settings such as health fairs, nonclinical locations, and other situations in which quickly receiving preliminary test results would be beneficial.

scholarly journals Biosensor Analysis of β-Lactams in Milk: Comparison with Microbiological, Immunological, and Receptor-Based Screening Methods

2004 ◽  
Vol 87 (3) ◽  
pp. 614-620 ◽  
Author(s):  
Eva Gustavsson ◽  
Åse Sternesjö
Keyword(s):  
False Negative ◽  
The Other ◽  
Screening Tests ◽  
Receptor Protein ◽  
Penicillin G ◽  
Screening Methods ◽  
Milk Samples ◽  
Negative Results ◽  
Developed Surface ◽  
Positive Results

Abstract Two recently developed surface plasmon resonance biosensor assays for detection of β-lactams in milk were used to screen raw producer milk samples. Both assays use a β-lactam receptor protein with carboxypeptidase activity for detection. The results of the biosensor assays were compared with those of various commercial screening tests, i.e., the Delvotest SP, Penzym S, Beta-STAR, SNAP, and Parallux. The results of the 2 biosensor assays showed good agreement with those of the other screening tests. Of 195 analyzed milk samples, the results of only 5 samples differed between the assays. Additionally, 30 milk samples with both negative and positive results in the screening assays were analyzed by liquid chromatography for identification and quantification of any β-lactam residues. All screening tests showed 0% false-negative results with 15 incurred samples containing between 4.0 and 268 μg/kg penicillin G. The biosensor assays showed 27% positive results (false violatives) with 15 producer milk samples containing penicillin G concentrations between 0 and 3.6 μg/kg, i.e., below maximum residue limit. This figure varied between 27 and 53% for the other screening tests.

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