High false positive rate of white blood cells in urine samples of pregnant women may be caused by epithelial cells being misclassified by the sysmex UF‐1000i urine flow cytometer

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.

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Hank’s balanced salt solution: an alternative resuspension medium to label autologous leukocytes. Experience in inflammatory bowel disease

Brazilian Archives of Biology and Technology ◽

10.1590/s1516-89132002000500006 ◽

2002 ◽

Vol 45 (spe) ◽

pp. 39-44 ◽

Cited By ~ 7

Author(s):

Joseph Martin-Comin ◽

Valbert Nascimento Cardoso ◽

Pedro Plaza ◽

Manoel Roca

Keyword(s):

Salt Solution ◽

Blood Cells ◽

Background Activity ◽

False Positive Rate ◽

White Blood Cells ◽

Labelling Efficiency ◽

Activity Ratios ◽

Positive Rate ◽

Inflammatory Bowel ◽

Group 1

In this work Hank's balanced salt solution (HBSS) has been used, as resuspension medium, instead of leukocyte poor plasma (LPP) to label autologous white blood cells in 28 patients with suspicion af active inflammatory bowel disease.Labelled cells were reinjected and anterior and caudo-craneal views were obtained at 30 min, 2 h and 6 h p.i. Regions of interest were outlined on liver, spleen, lung, bone marrow (spine), background and lesions and the organ/background activity ratios were calculated in all scans. Patients were classified into 2 groups: Group 1: LPP, 30 patients and Groups 2: HBSS, 28 patients. Labelling efficiency was higher in HBBS group (89.0 ± 3.2 %) than in the LPP group (6.5 ± 6.3%). Organ/background activity ratios were similar in both groups. Concerning diagnostic accuracy was similar at 30 min and 2 h but the false positive rate increased at 6 h p.i. in the HBSS group. HBSS seems to be a valid alternative as resuspension medium in the labeling of autologous leukocytes but leukocyte poor plasma seem to induce less leukocyte damage. Based on these results, in our center HBSS is the currently used medium to label leukocytes.

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Predicting first-trimester outcome of embryos with cardiac activity in women with recurrent spontaneous abortion

Journal of International Medical Research ◽

10.1177/0300060520911829 ◽

2020 ◽

Vol 48 (6) ◽

pp. 030006052091182

Author(s):

Huixian Li ◽

Shuang Qin ◽

Fanfan Xiao ◽

Yuhong Li ◽

Yunhe Gao ◽

...

Keyword(s):

Pregnant Women ◽

False Positive ◽

Detection Rate ◽

False Positive Rate ◽

Cardiac Activity ◽

First Trimester ◽

Clinical Indicators ◽

Early Outcome ◽

Heart Motion ◽

Positive Rate

Objective This study was performed to evaluate the capability of routine clinical indicators to predict the early outcome of embryos with cardiac activity in women with recurrent spontaneous abortion (RSA). Methods A retrospective cohort study of pregnant women with a history of RSA in a Chinese tertiary hospital was performed using unadjusted and multivariable logistic regression. Results Of 789 pregnant women with RSA, 625 (79.21%) had ongoing pregnancy, whereas 164 (20.79%) developed abortion before 20 full weeks of gestational age even after embryonic heart motion was detected. The final model had an area under the curve of 0.81 (95% confidence interval, 0.78–0.84) with a sensitivity of 74.39%, a specificity of 76.00%, and a false-positive rate of 52.32% at a fixed detection rate of 90%. Conclusions The combination of multiple routine clinical indicators was valuable in predicting the early outcome of embryos with cardiac activity in viable pregnancies with RSA. However, this model might result in a high false-positive rate with a fixed detection rate of 90%; other markers must be investigated to identify first-trimester RSA once positive embryonic heart motion is established.

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Second Trimester Screening of Preeclampsia Using Maternal Characteristics and Uterine and Ophthalmic Artery Doppler

Ultraschall in der Medizin - European Journal of Ultrasound ◽

10.1055/s-0042-104649 ◽

2016 ◽

Vol 39 (02) ◽

pp. 190-197 ◽

Cited By ~ 3

Author(s):

Paulo Praciano de Souza ◽

Júlio Gurgel Alves ◽

Sammya Bezerra Maia e Holanda Moura ◽

Edward Araujo Júnior ◽

Wellington Martins ◽

...

Keyword(s):

Pregnant Women ◽

False Positive ◽

Ophthalmic Artery ◽

False Positive Rate ◽

Categorical Variables ◽

Second Trimester ◽

Maternal Characteristics ◽

Maternal Risk ◽

Second Trimester Screening ◽

Positive Rate

Abstract Purpose To establish the performance of a multi-parametric test including maternal risk factors and maternal uterine and ophthalmic artery Doppler in the second trimester of pregnancy for the prediction of preeclampsia (PE). Materials and Methods We performed a prospective observational cohort study with pregnant women who underwent a second trimester morphology scan. Maternal uterine and ophthalmic artery Doppler examinations were performed in 415 singleton pregnancies between 18 and 23 weeks of gestation. Additional history was obtained through participant questionnaires, and follow-up occurred to the time of discharge post-delivery. The control and PE groups were compared to continuous variables using the Kruskal-Wallis test and to categorical variables using the Chi-square and Fisher exact tests. Univariate and multivariate logistic regression analyses were performed to determine the best model for the prediction of PE. Results 40 (9.6 %) pregnant women developed PE. We observed significant differences in the body mass index (BMI) (p < 0.001), parity (p < 0.001), mean arterial pressure (MAP) (p < 0.001), and pulsatility index (PI) of uterine artery Doppler (p < 0.001) between PE and control groups. The best model for the prediction of PE included maternal characteristics, MAP, maternal uterine and ophthalmic artery Doppler with area under receiver operating characteristics (ROC) curve of 0.710 (95 % confidence interval, 613 – 0.807) with a sensitivity of 45 % to a false-positive rate of 10 % and 35 % to a false-positive rate of 5 %. Conclusion Maternal ophthalmic artery Doppler did not promote a significant increase in the PE detection rate during the second trimester scan.

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Pneumatic tube transportation of urine samples

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2020-1198 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Eline Sandvig Andersen ◽

Ivan Brandslund

Keyword(s):

Epithelial Cells ◽

Red Blood Cells ◽

Blood Cells ◽

White Blood Cells ◽

Urine Samples ◽

Tube System ◽

Pneumatic Tube ◽

Local Quality ◽

Renal Tubular ◽

Pneumatic Tube System

AbstractObjectivesPneumatic tube transportation of samples is an effective way of reducing turn-around-time, but evidence of the effect of pneumatic tube transportation on urine samples is lacking. We thus wished to investigate the effect of pneumatic tube transportation on various components in urine, in order to determine if pneumatic tube transportation of these samples is feasible.MethodsOne-hundred fresh urine samples were collected in outpatient clinics and partitioned with one partition being carried by courier to the laboratory, while the other was sent by pneumatic tube system (Tempus600). Both partitions were then analysed for soluble components and particles, and the resulting mean difference and limits of agreement were calculated.ResultsAlbumin, urea nitrogen, creatinine, protein and squamous epithelial cells were unaffected by transportation in the Tempus600 system, while bacteria, renal tubular epithelial cells, white blood cells and red blood cells were affected and potassium and sodium may have been affected.ConclusionsThough pneumatic tube transportation did affect some of the investigated components, in most cases the changes induced were clinically acceptable, and hence samples could be safely transported by the Tempus600 pneumatic tube system. For bacteria, white blood cells and red blood cells local quality demands will determine if pneumatic tube transportation is appropriate.

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SARS-CoV-2 immunochromatographic IgM/IgG rapid test in pregnancy: A false friend?

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/0004563220980495 ◽

2020 ◽

pp. 000456322098049

Author(s):

M Fabre ◽

S Ruiz-Martinez ◽

ME Monserrat Cantera ◽

A Cortizo Garrido ◽

Z Beunza Fabra ◽

...

Keyword(s):

Positive Predictive Value ◽

Pregnant Women ◽

Predictive Value ◽

False Positive ◽

Screening Tool ◽

False Positive Rate ◽

Rapid Test ◽

Immunochromatographic Assay ◽

Qualitative Detection ◽

Positive Rate

Background An increasing body of evidence has revealed that SARS-CoV-2 infection in pregnant women could increase the risk of adverse maternal and fetal outcomes. Careful monitoring of pregnancies with COVID-19 and measures to prevent neonatal infection are warranted. Therefore, rapid antibody tests have been suggested as an efficient screening tool during pregnancy. Cases We analysed the clinical performance during pregnancy of a rapid, lateral-flow immunochromatographic assay for qualitative detection of SARS-CoV-2 IgG/IgM antibodies. We performed a universal screening including 169 patients during their last trimester of pregnancy. We present a series of 14 patients with positive SARS-CoV-2 immunochromatographic assay rapid test result. Immunochromatographic assay results were always confirmed by chemiluminescent microparticle immunoassays for quantitative detection of SARS-CoV-2 IgG and IgM+IgA antibodies as the gold standard. We observed a positive predictive value of 50% and a false positive rate of 50% in pregnant women, involving a significantly lower diagnostic performance than reported in non-pregnant patients. Discussion Our data suggest that although immunochromatographic assay rapid tests may be a fast and profitable screening tool for SARS-CoV-2 infection, they may have a high false positive rate and low positive predictive value in pregnant women. Therefore, immunochromatographic assay for qualitative detection of SARS-CoV-2 IgG/IgM antibodies must be verified by other test in pregnant patients.

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Effectiveness of Alpha-Fetoprotein Variants L2 and L3 as Substitutes of Alpha-Fetoprotein in Screening for Fetal Trisomy 18

10.21203/rs.2.13899/v1 ◽

2019 ◽

Author(s):

Jianxia Huang ◽

Yiming Chen ◽

Wensheng Hu

Keyword(s):

Pregnant Women ◽

False Positive ◽

False Positive Rate ◽

Alpha Fetoprotein ◽

Trisomy 18 ◽

Control Group ◽

Optimal Cutoff ◽

Marker Combination ◽

Positive Rate ◽

Β Hcg

Abstract Purpose To evaluate the effectiveness of alpha-fetoprotein variants (AFP-L2, AFP-L3) for fetal screening of Trisomy 18 in place of alpha fetoprotein (AFP). Methods A case-control study was conducted. The case group included 39 pregnant women diagnosed by karyotype analysis of amniotic fluid cells as bearing Trisomy 18 fetuses. The control group included 48 pregnant women with clinically normal and healthy fetal development. The serum AFP-L2 and AFP-L3 concentrations were detected. Receiver operating characteristic (ROC) curves were used to determine the optimal cutoff value, area under the curve (AUC), and assess the screening performance of AFP-L2 and AFP-L3. Results The AFP-L2 and AFP-L3 concentrations in pregnant women with Trisomy 18 fetuses were 7.95±3.57 ng/mL , and 2.53±1.80 ng/mL, respectively, which was significantly higher than those of the control group (3.73±1.63 ng/mL [3.26~4.20], t=6.820, P<0.001, and 0.84±0.60 ng/mL [0.66~1.01], t=5. 588, P<0.001, respectively). The AUC for AFP-L2 and AFP-L3 in screened Trisomy 18 fetuses was 0.848 (95% CI: 0.767-0.930, P < 0.001) and 0.806 (95% CI: 0.707-0.905, P < 0.001), respectively. The optimal cutoff values of AFP-L2 and AFP-L3 for Trisomy 18 fetuses were determined to be 6.340 ng/mL and 1.705 ng/mL, respectively. The corresponding sensitivity, specificity, and Youden index values were 0.615, 1.000, 0.615; 0.6410, 0.958, and 0.599, respectively. Comparisons across multiple modeling methods showed that the highest AUC of screened Trisomy 18 fetuses (0.992 and 0.986) was yielded by AFP-L2 + AFP-L3 + free β-HCG, and AFP-L2 + free β-HCG, with 1.000 sensitivity indicated in both instances. The sensitivities of the four Trisomy 18 screening combinations were all 1.000. In the control group, false positive rates of 22.92%, 8.33%, 12.50%, and 12.50% were observed. The series test showed that the sensitivities of Trisomy 18 screening was 69.23%, 61.54%, 64.10%, and 43.59%, respectively, while a 3.28% false positive rate was found in the control group AFP + free β-HCG marker combination. Conclusion AFP-L2 and AFP-L3 showed high sensitivity and specificity in the screening of fetuses for Trisomy 18. The new indicators did not bring about a significant improvement in screening efficiency but false positive rate was reduced compared to AFP.

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First Trimester Genetic Sonogram for Screening Fetal Down Syndrome: a Population-based Study

10.21203/rs.3.rs-48430/v1 ◽

2020 ◽

Author(s):

Kuntharee Traisrisilp ◽

Supatra Sirichotiyakul ◽

Fuanglada Tongprasert ◽

Kasemsri Srisupun ◽

Suchaya Luewan ◽

...

Keyword(s):

Down Syndrome ◽

Pregnant Women ◽

False Positive ◽

Detection Rate ◽

False Positive Rate ◽

Nasal Bone ◽

First Trimester ◽

Nuchal Translucency ◽

Ductus Venosus ◽

Positive Rate

Abstract Background: To evaluate the performance of first trimester sonomarkers in the detection of fetal Down syndrome among Thai pregnant womenMethods: Pregnant women at 11-13+6 weeks’ gestation underwent ultrasound examination for assessment of nuchal translucency (NT), nasal bone (NB), tricuspid regurgitation (TR), and abnormal ductus venosus (aDV) Doppler waveforms. The women were followed up for final outcomes. Fetal abnormalities other than trisomy 21 were excluded. The performances of each sonomarker and their combinations in predicting fetal Down syndrome were calculated.Results: A total of 7,820 pregnant women meeting the inclusion criteria were available for analysis, including 20 cases with fetal Down syndrome and 7,800 unaffected cases. Of the four sonomarkers, NT, as a single sonomarker, had the highest detection rate (55.0% at a false positive rate of about 5%), whereas the remaining single sonomarkers had low detection rate (15-20%). The combination of all sonomarkers had the highest detection rate of 70% but the false positive rate was as high as 10.8%. The combination of NT and NB had a detection rate of 60% with an acceptable false positive rate of 6.9%, whereas the other combinations yielded relatively high false positive rates. Conclusion: The first trimester genetic sonogram in screening for Down syndrome among Asian women is acceptably effective and may be offered to some selected groups of the population. NT is the best sonomarker with a detection rate of 55% at 5% false positive rate and its combination with NB can improve performance with minimal increase in false positive rate.

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Improving diagnosis of acute appendicitis with atypical findings by Tc-99m HMPAO leukocyte scan

Nuklearmedizin ◽

10.1055/s-0038-1623994 ◽

2002 ◽

Vol 41 (01) ◽

pp. 37-41 ◽

Cited By ~ 3

Author(s):

S. Shung-Shung ◽

S. Yu-Chien ◽

Y. Mei-Due ◽

W. Hwei-Chung ◽

A. Kao

Keyword(s):

Acute Appendicitis ◽

False Positive ◽

False Positive Rate ◽

Accurate Method ◽

Clinical Findings ◽

Pathological Findings ◽

Lower Quadrant ◽

Predictive Values ◽

Positive Rate

Summary Aim: Even with careful observation, the overall false-positive rate of laparotomy remains 10-15% when acute appendicitis was suspected. Therefore, the clinical efficacy of Tc-99m HMPAO labeled leukocyte (TC-WBC) scan for the diagnosis of acute appendicitis in patients presenting with atypical clinical findings is assessed. Patients and Methods: Eighty patients presenting with acute abdominal pain and possible acute appendicitis but atypical findings were included in this study. After intravenous injection of TC-WBC, serial anterior abdominal/pelvic images at 30, 60, 120 and 240 min with 800k counts were obtained with a gamma camera. Any abnormal localization of radioactivity in the right lower quadrant of the abdomen, equal to or greater than bone marrow activity, was considered as a positive scan. Results: 36 out of 49 patients showing positive TC-WBC scans received appendectomy. They all proved to have positive pathological findings. Five positive TC-WBC were not related to acute appendicitis, because of other pathological lesions. Eight patients were not operated and clinical follow-up after one month revealed no acute abdominal condition. Three of 31 patients with negative TC-WBC scans received appendectomy. They also presented positive pathological findings. The remaining 28 patients did not receive operations and revealed no evidence of appendicitis after at least one month of follow-up. The overall sensitivity, specificity, accuracy, positive and negative predictive values for TC-WBC scan to diagnose acute appendicitis were 92, 78, 86, 82, and 90%, respectively. Conclusion: TC-WBC scan provides a rapid and highly accurate method for the diagnosis of acute appendicitis in patients with equivocal clinical examination. It proved useful in reducing the false-positive rate of laparotomy and shortens the time necessary for clinical observation.

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Predicting Fetal Chromosome Anomalies in the First Trimester Using Pregnancy Associated Plasma Protein-A: A Comparison of Statistical Methods

Methods of Information in Medicine ◽

10.1055/s-0038-1634910 ◽

1993 ◽

Vol 32 (02) ◽

pp. 175-179 ◽

Cited By ~ 7

Author(s):

B. Brambati ◽

T. Chard ◽

J. G. Grudzinskas ◽

M. C. M. Macintosh

Keyword(s):

Logistic Regression ◽

General Population ◽

Likelihood Ratio ◽

False Positive ◽

False Positive Rate ◽

Ratio Method ◽

Detection Rates ◽

Gaussian Distributions ◽

Positive Rate ◽

Likelihood Ratio Method

Abstract:The analysis of the clinical efficiency of a biochemical parameter in the prediction of chromosome anomalies is described, using a database of 475 cases including 30 abnormalities. A comparison was made of two different approaches to the statistical analysis: the use of Gaussian frequency distributions and likelihood ratios, and logistic regression. Both methods computed that for a 5% false-positive rate approximately 60% of anomalies are detected on the basis of maternal age and serum PAPP-A. The logistic regression analysis is appropriate where the outcome variable (chromosome anomaly) is binary and the detection rates refer to the original data only. The likelihood ratio method is used to predict the outcome in the general population. The latter method depends on the data or some transformation of the data fitting a known frequency distribution (Gaussian in this case). The precision of the predicted detection rates is limited by the small sample of abnormals (30 cases). Varying the means and standard deviations (to the limits of their 95% confidence intervals) of the fitted log Gaussian distributions resulted in a detection rate varying between 42% and 79% for a 5% false-positive rate. Thus, although the likelihood ratio method is potentially the better method in determining the usefulness of a test in the general population, larger numbers of abnormal cases are required to stabilise the means and standard deviations of the fitted log Gaussian distributions.

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