Test Cut-off Point Research Articles

Moderate-to-high normal levels of thyrotropin is a risk factor for urinary incontinence and an unsuitable quality of life in women over 65years.

The present study aimed to investigate the relationship between normal serum concentrations of thyrotropin (TSH) and urinary incontinence (IU), urinary infections, and quality of life in old women. Euthyroid post-menopausal women without sarcopenia, estrogen replacement, emotional illness, and/or cancer were enrolled as participants. Anthropometric indicators, serum glucose and estradiol, and thyroid profile were measured. Sociodemographic, clinical, physical activity, and quality of life (SF-36) surveys were applied. One-hour pad test and International Consultation on Incontinence Questionnaire Short Form (ICIQ-SF) were used to determine UI. Urinalysis was also done. In agreement with results from the pad test (cut-off point ≥1.4g), the ICIQ-SF reveled approximately 50% of incontinent women. A high percentage of women had moderate-high bacteriuria and urinary infections. Logistic regression analysis showed that age is a risk factor for both UI and urinary infection. Diabetes, number of pregnancies or childbirths, urinary infections, and bacteriuria did not influence the presence of UI. To allocate women into four groups according to their age (<65 or ≥65years old) and TSH concentrations (0.3-1.9 or 2-10μUI/mL), we found that moderate-to-high normal levels of TSH is a risk factor for UI and a worse quality of life in the oldest women. Our results highlight the profit of measuring TSH concentrations in post-menopausal women.

Standardization and Prevalence of the Booster Phenomenon: Evaluation Using a Two-Step Skin Test with 43kDa Glycoprotein in Individuals from an Endemic Region of Paracoccidioidomycosis.

We estimated the occurrence rate of the booster phenomenon by using an intradermal test with 43kDa glycoprotein in an endemic area of paracoccidioidomycosis in the central-west region of Brazil. Individuals who had a negative result on a survey performed by using an intradermal test with 43kDa glycoprotein in an endemic area of paracoccidioidomycosis underwent a second intradermal test after 10-15days to determine the presence or absence of the booster phenomenon. Statistical analyses were performed using the Chi-square test, Chi-square for linear trend test, Student's t test, and binomial test; p<0.05 was considered significant. For the first time, we reported the occurrence of the booster phenomenon to an intradermal reaction caused by 43kDa glycoprotein at a rate of 5.8-8.4%, depending on the test's cutoff point. This suggests that a cutoff point should be considered for the booster phenomenon in intradermal tests with 43kDa glycoprotein: a difference of 6-7mm between readings according to the first and second tests, depending on the purpose of the evaluation. The results indicate that the prevalence of paracoccidioidal infection in endemic areas is underestimated, as the booster phenomenon has not been considered in epidemiological surveys for this infection.

Variability in the use of cut-off points with different commercial and lab-developed assays for PD-L1 expression testing in the NSCLC clinical setting in the United States.

46 Background: Following the recent approval of several companion diagnostic and complementary diagnostic assays for PD-L1 expression testing, as well as the availability of multiple antibodies for use in laboratory testing, pathologists have a range of tools at their disposal for measuring expression levels of this predictive biomarker. While specific cut-off points for positivity are specified by the assay manufacturer and/or recommended based on trial data, clinicians can choose different cut-off points to define positivity. In this study, we explore the variety of test brands and cut-off points that are being used in clinical practice in the US by examining real-world usage data. Methods: Between June and August 2016, a panel of pathologists (n = 27) in the US were asked to report on their practices relating to PD-L1 expression testing for NSCLC patients, through the submission of online de-identified record forms (n = 167 PD-L1-tested samples). Results: Of the 167 samples, 112 (67%) were tested with the Dako 22C3 pharmDx assay, 37 (22%) with the Dako 28-8 pharmDx assay and 16 (10%) with a lab-developed test (LDT). When using 22C3 pharmDx, 72% of samples were tested with the recommended 50% cut-off point, with the remaining 28% using lower cut-off points, ranging from 1% to 25%. For 28-8 pharmDx, both the 1% cut-off point (in 54% of cases) and the 5% cut-off point (in 35% of cases) were frequently used (1% recommended; 5% being investigated in clinical trials e.g. CHEKMATE-026). LDTs were mostly (88%) employed with a cut-off of 1% across antibodies. Conclusions: The use of PD-L1 expression testing to determine eligibility for PD-(L)1 inhibitors in the clinical setting shows significant fragmentation in the US, with multiple different assays being employed. Furthermore, there is a lack of standardization in terms of the cut-off points that are used when testing with each of those assays. This lack of consistency adds a level of complexity to oncologists treatment decisions when choosing whether or not to treat with a PD-(L)1 inhibitor, and which brand to choose.

The clinical utility of naturalistic action test in differentiating mild cognitive impairment from early dementia in memory clinic.

This study aimed to examine the validity of the Naturalistic Action Test in differentiating Mild Cognitive Impairment from early dementia compared to clinical diagnosis and ascertain Naturalistic Action Test cut-off points. This was a cross-sectional study of 70 consecutive patients diagnosed with Mild Cognitive Impairment attending the memory clinic in St James's Hospital, Dublin, Ireland. Patients with a diagnosis of Mild Cognitive Impairment who attended for routine annual assessment were asked to participate in the study. The Naturalistic Action Test was carried out after the patient had completed their routine assessment in the clinic. The Area under the Curve, AUC ± SE was 0.808 ± 0.058, p < 0.001 with 95% CI (0.695-0.922). There was concordance in 40 and discrepancy in 30 patients between the NAT and the gold standard consensus diagnosis (PPV 38%, NPV 96%, sensitivity 94%, specificity 46% and accuracy 59%) using cut-off point of ≥14 for normal function on Naturalistic Action Test. The difference was not related to age, sex, level of education or informant. Using the Youden index, we determined a Naturalistic Action Test cut-off score of ≥11 for Mild Cognitive Impairment in our study (PPV 50%, NPV 91%, sensitivity 78%, specificity 73% and accuracy of 74%). There was discrepancy in 18 patients using the new cut-off point (≥11 for Mild Cognitive Impairment vs ≤10 for dementia). The Naturalistic Action Test is a useful tool that can increase diagnostic accuracy in differentiating Mild Cognitive Impairment from early dementia.

Prevalence of Alcohol Problem Drinking Among the Indigenous Population in Colombia

BackgroundSome studies have reported a high prevalence of alcohol drinking problem among indigenous populations in Latin America. However, there is no available information on some of the variables associated with alcohol problem drinking. ObjectiveTo determine the prevalence and some factors associated with alcohol problem drinking among a sample of Colombian indigenous population in Bogotá, Colombia. MethodA cross-sectional study was conducted using a Colombian indigenous population sample over 15 years old living in the community. Alcohol problem drinking was quantified with the Alcohol Use Disorders Identification Test (AUDIT) (Cut-off point of 8). Non conditional logistic regression was computed to adjust associated variables. ResultsA total of 184 subjects from the indigenous population participated in this research. The mean age was 32.0±14.0 years and educated for 6.0±3.7 years. A total of 84 participants (45.7%) reported alcohol problem drinking. The AUDIT showed Cronbach alpha of 0.877. Male sex (OR=4.2; 95%CI, 2.2–7.6), and longer time living in Bogota (OR=1.8; 95%CI, 1.0–3.2) were associated with alcohol problem drinking. ConclusionsAlmost 50% of the Colombian indigenous population living in Bogota meet criteria for alcohol problem drinking. Male gender and longer time living in Bogota are related to alcohol problem drinking. Further studies are needed to formally identify alcohol abuse or dependence.

Recognizing internet addiction: Prevalence and relationship to academic achievement in adolescents enrolled in urban and rural Greek high schools

This study aims: a) to estimate the prevalence of internet addiction among adolescents of urban and rural areas in Greece, b) to examine whether the Internet Addiction Test cut-off point is applicable to them and c) to investigate the phenomenon's association with academic achievement. Participants were 2090 adolescents (mean age 16, 1036 males, 1050 females). Young's (1998) Internet Addiction Test and her Diagnostic Questionnaire were applied. School records' grades were retrieved. A 3.1% prevalence revealed, while boys {F (1, 1642) = 6.207, p < .05}, urban residents {F (1, 1642) = 5.53, p > .05} and academic track high school students {F (1, 1642) = 5.30, p < .05} were at higher risk. An Internet Addiction Test score of 51 points (sample's mean = 27.69, SD = 17.38) was proposed as the optimal cut-off point combining high sensitivity (98%) and specificity (91%). Finally, findings illustrated the syndrome's relation to worse academic achievement {F (1, 1725) = 0.93, p > .05}.

Aptidão cardiorrespiratória em adolescentes estimada pelo teste de corrida e/ou caminhada de 9 minutos.

1 Abstract - The aim of this study was to analyze estimation of cardiorespiratory fitness (CRF) in adolescents aged 10 to 12 years by means of the 9-minute run/walk test. A total of 115 adolescents (61 boys and 54 girls) took part in the study. Mean age was 12.2±0.9 and 12.1±0.7 years, body mass 47.5±13.6 and 45.0±13.2 kg, height 150.9±7.7and 150.4±7.3 cm, and VO 2 peak 49.9±9.5 and 42.2±7.4 mL/kg/min in boys and girls respectively. The subjects performed a maximal treadmill test and a 9-minute run/walk field test (9-minute test). The relationship between VO 2 and the 9-minute test was analyzed by Pearson's correlation coefficient. The difference between the proportions of adolescents who met health criteria and agreement between the CRF cutoff points proposed in the Physical Best and Fitnessgram batteries was analyzed with McNemar's test and the Kappa sta- tistic respectively. The significance level was set at 5%. There was moderate correlation (r=0.64) between the 9-minute test and directly measured VO 2 peak in the sample as a whole. Gender-stratified analysis showed higher correlation in boys (r=0.59) than in girls (r=0.43). There were significant differences between the tested cutoff points (P<0.001) and weak agreement (Kappa = 0.19) in relation to CRF. These findings suggest that the 9-minute test appears to be a valid indicator of CRF in adolescents between the ages of 10 and 12. However, care should be taken when choosing cutoff points for classification of cardiorespiratory fitness.

Screening for Tuberculosis Infection in Spanish Healthcare Workers Comparison of the QuantiFERON-TB Gold In-Tube Test with the Tuberculin Skin Test

The risk of latent tuberculosis (LTBI) in healthcare workers (HCWs) is high. Until recently, the tuberculin skin test (TST) was the only diagnostic test available for Mycobacterium tuberculosis infection. A new enzyme-linked immunosorbent assay test, the QuantiFERON-TB Gold (QFT-G) test, was recommended by the US Centers for Disease Control and Prevention as an alternative test for the diagnosis of LTBI in HCWs. The purpose of our study was to compare the TST and the QFT-G test in Spanish HCWs in order to improve procedures for the detection of LTBI. A cross-sectional study with blinded comparison of TST and QFT-G test results was carried out among 134 HCWs at an 800-bed Spanish university hospital. The level of interferon-gamma production stimulated by the QFT-G test was measured. A concentration of at least 0.35 IU/mL was considered a positive result. An induration of at least 5 mm in non-BCG-vaccinated or at least 15 mm in BCG-vaccinated HCWs for the TST was considered positive. Of the 134 HCWs included (mean age, 33.4 years; 101 [75.4%] women; 47 [35.1%] BCG vaccinated), the LTBI prevalence diagnosed with any test was 11.2% (95% confidence interval, 6.6%-18.1%), with the TST was 8.96%, and with the QFT-G test was 5.97% (nonsignificant differences). The QFT-G test value was higher in subjects with TST induration of at least 15 mm than in subjects with TST induration of less than 15 mm (P < .001). Overall agreement between the results of the two tests was found in 94% of HCWs (kappa = 0.56), but agreement was only 59% in HCWs who had a positive result for both tests. Disagreement was present in the results found for 5% of HCWs. Few studies have compared both tests in populations with high M. tuberculosis exposure but low BCG vaccination prevalence. Agreement between both tests is high, especially among negative results. Studies are needed to clarify the reasons for disagreement and to establish the best TST and QFT-G test cutoff point.

PERBANDINGAN KADAR SOLUBLE fms-LIKE TYROSINE KINASE 1 (sFlt1) SERUM KEHAMILAN NORMAL DENGAN PREEKLAMSI BERAT SERTA HUBUNGANNYA DENGAN TEKANAN DARAH DAN DERAJAT PROTEINURIA

Prediction and early detection of preclampsia is very important to reduce maternal and maternal and perinatal morbidity and mortality. This researchwas to find out the difference of serum sFIf1 level between normal pregnancy and severe preeclampsia (SPE) and to determine the corelation of serum sFIt1 level with blood pressure as well as the degree of potentenuria. This was an analytic observational cross sectional study. Measurement of serum sFIt1 level using ELISA. Statistical analysis was performed by using chi square, t test. Mann-Whitney test, Spearman Rank correlation coefficient and diagnosis test cut-off point determination. The characteristics of the subjects in both groups were not statistically different (p>0.05). There was a significant difference insFIt1 level between SPE group and control group (3.827±471 pg/mL and 2,708±441 pg/mL subsequently;≤0.05). There were significant association between sFIt1 level and systolic blood pressure (p=0.042; p≤0.05), betweem sFIt1 level and diastolic blood pressure (p=0.041;p≤0.05), and between sFIt1 level and degree of proteinuria (p=0.012; P

No decrease in annual risk of tuberculosis infection in endemic area in Cape Town, South Africa

To estimate the change in annual risk of tuberculosis infection (ARTI) in two neighbouring urban communities of Cape Town, South Africa with an HIV prevalence of approximately 2%, and to compare ARTI with notification rates and treatment outcomes in the tuberculosis (TB) programme. In 1998-1999 and 2005, tuberculin skin test surveys were conducted to measure the prevalence of Mycobacterium tuberculosis infection and to calculate the ARTI. All 6 to 9-year-old children from all primary schools were included in the survey. Notification rates and treatment outcomes were obtained from the TB register. A total of 2067 children participated in the survey from 1998 to 1999 and a total of 1954 in 2005. Based on a tuberculin skin test cut-off point of 10 mm, the ARTI was 3.7% (3.4-4.0%) in the 1998-1999 survey and 4.1% (3.8-4.5%) in 2005. The notification rate for pulmonary TB increased significantly from 646 per 100 000 in 1998 to 784 per 100,000 in 2002. In Ravensmead, there was no significant change in ARTI [first survey: 3.5% (3.1-3.9%), second survey: 3.2% (2.9-3.6%)], but in Uitsig the ARTI increased significantly from 4.1% (3.6-4.6%) to 5.8% (5.2-6.5%). The difference in ARTI between the two areas was associated with differences in reported case rates and the proportion of previously treated cases. Tuberculosis transmission remains very high in these two communities and control measures to date have failed. Additional measures to control TB are needed.

Influence of Lower Cutoff Values for 100-G Oral Glucose Tolerance Test and Glycemic Profile for Identification of Pregnant Women at Excessive Fetal Growth Risk

To evaluate data from patients with normal oral glucose tolerance test (OGTT) results and a normal or impaired glycemic profile (GP) to determine whether lower cutoff values for the OGTT and GP (alone or combined) could identify pregnant women at risk for excessive fetal growth. We classified 701 pregnant women with positive screening for gestational diabetes mellitus (GDM) into 2 categories -- (1) normal 100-g OGTT and normal GP and (2) normal 100-g OGTT and impaired GP-to evaluate the influence of lower cutoff points in a 100-g OGTT and GP (alone or in combination) for identification of pregnant women at excessive fetal growth risk. The OGTT is considered impaired if 2 or more values are above the normal range, and the GP is impaired if the fasting glucose level or at least 1 postprandial glucose value is above the normal range. To establish the criteria for the OGTT (for fasting and 1, 2, and 3 hours after an oral glucose load, respectively), we considered the mean (75 mg/dL, 120 mg/dL, 113 mg/dL, and 97 mg/dL), mean plus 1 SD (85 mg/dL, 151 mg/dL, 133 mg/dL, and 118 mg/dL), and mean plus 2 SD (95 mg/dL, 182 mg/dL, 153 mg/dL, and 139 mg/dL); and for the GP, we considered the mean and mean plus 1 SD (78 mg/dL and 92 mg/dL for fasting glucose levels and 90 mg/dL and 130 mg/dL for 1- or 2-hour postprandial glucose levels, respectively). Subsequently, the women were reclassified according to the new cutoff points for both tests (OGTT and GP). Consideration of values, in isolation or combination, yielded 6 new diagnostic criteria. Excessive fetal growth was the response variable for analysis of the new cutoff points. Odds ratios and their respective confidence intervals were estimated, as were the sensitivity and specificity related to diagnosis of excessive fetal growth for each criterion. The new cutoff points for the tests, when used independently rather than collectively, did not help to predict excessive fetal growth in the presence of mild hyperglycemia. Decreasing the cutoff point for the 100-g OGTT (for fasting and 1, 2, and 3 hours) to the mean (75 mg/dL, 120 mg/dL, 113 mg/dL, and 97 mg/dL) in association with the GP (mean or mean plus 1 SD-78 mg/dL and 92 mg/dL for the fasting state and 90 mg/dL and 130 mg/dL for 1- or 2-hour postprandial values-increased the sensitivity and specificity, and both criteria had statistically significant predictive power for detection of excessive fetal growth.

Appraisal of interpretation criteria for the comparative intradermal tuberculin test for diagnosis of tuberculosis in cattle in central Ethiopia.

Accurate detection and removal of infected cattle, using immunodiagnostic tests such as the comparative intradermal tuberculin (CIDT) test, are the basis of control strategies for bovine tuberculosis (TB). According to the Office des Internationale Epizooties recommendation, the cutoff point for positivity of the CIDT test, calculated as the difference between skin thicknesses after bovine tuberculin (B) and avian tuberculin (A) injections (B - A), is >4 mm. This cutoff point is used worldwide, although it is likely that local conditions influence test performance. Thus, this study was formulated to determine CIDT test cutoff points applicable to cattle in central Ethiopia. Receiver operating characteristic analysis was performed for the CIDT test, using data from 186 Bos indicus (zebu) and Bos taurus (Holstein) cattle. Detailed postmortem examination for the presence of TB lesions was used to define disease status. At a cutoff of >2 mm, CIDT test sensitivity was 69% (95% confidence interval [95% CI], 58.5 to 79%), while it was 59% (95% CI, 49 to 69%) at a cutoff of >4 mm. In contrast, specificities of the CIDT test at these two cutoff values were identical, at 97% (95% CI, 89 to 100%). Thus, the maximum sensitivity of the CIDT test can be realized using a >2-mm cutoff without affecting specificity. The apparent prevalence was significantly (chi(2) = 13.56; P < 0.001) higher at a cutoff of >2 mm (16.0%; n = 5,424) than at a >4-mm cutoff (13.5%; n = 5,424). Nonetheless, no significant difference (chi(2) = 2.15; P = 0.14) in true prevalence was observed at a cutoff of >2 mm (19.6%) and at a cutoff of >4 mm (18.5%). Thus, our study demonstrates the importance of defining local, relevant cutoff values to maximize test sensitivity, and we suggest the application of the >2-mm cutoff for testing of cattle in central Ethiopia.

Validez del cuestionario AUDIT para la detección de problemas relacionados con el consumo de alcohol en mujeres

Early detection of patients with alcohol problems is important in clinical practice. The AUDIT (Alcohol Use Disorders Identification Test) questionnaire is a valid tool for this aim, especially in the male population. The objective of this study was to validate how useful is this questionnaire in females patients and to assess their test cut-off point for the diagnosis of alcohol problems in women. 414 woman were recruited in 2 health center and specialized center for addiction treatment. The AUDIT test and a semistructured interview (SCAN as gold standard) were performed to all patients. Internal consistency and criteria validity was assessed. Cronbach alpha was 0.93 (95% confidence interval [CI], 0.921-0.941). When the DSM-IV was taken as reference the most useful cut-off point was 6 points, with 89.6% (95% CI, 76.11-96.02) sensitivity and 95.07% (95% CI, 92.18-96.97) specificity. When CIE-10 was taken as reference the sensitivity was 89.58% (95% CI, 76.56-96.10) and the specificity was 95.33% (95% CI, 92.48-97.17). AUDIT is a questionnaire with good psychometrics properties and is valid for detecting dependence and risk alcohol consumption in women.

Validation of Michigan neuropathy screening instrument for diabetic peripheral neuropathy

Objective The reliability and accuracy of the Michigan neuropathy screening instrument (MNSI) have been discussed recently. As a result of the difficulties of performing and analyzing nerve biopsy as a standard diagnostic test, electromyography and neuronography is used as the best alternative diagnostic procedure. The objective of this study was to determine the diagnostic performance of the test characteristics and cut-off point of MNSI scoring for the diagnosis of diabetic peripheral neuropathy. Method Over a 2-year period, a cross-sectional study was conducted on 176 type 2 diabetic patients. An internist carried out the MNSI and the sum of scores varying from 0 to 1 for each abnormality as revealed in foot appearance, ulceration, ankle reflexes and vibratory perception has been recorded. A neurologist, who was blind to the MNSI scores, performed all neurophysiological studies. The test performance characteristics of the MNSI procedure were measured for different cut-off values. Results MNSI scores of 1.5, 2.0, 2.5 and 3.0 were assessed as cut-off values. Sensitivities were 79%, 65%, 50% and 35% and specificities were 65%, 83%, 91% and 94%, respectively. Positive predictive values increased and negative predictive values decreased for each score. Accuracies, likelihood ratios and post-test probabilities were measured. Conclusion The accuracy of MNSI scoring makes it a useful screening test for diabetic neuropathy in taking a decision regarding which patients should be referred to a neurologist for electrophysiological studies. High specificity, likelihood ratios over 5 and a moderate to good post-test probability give a high diagnostic impact for MNSI scoring. We suggest a cut-off point of 2 for the MNSI procedure. However, electrophysiological studies should be considered when the patient has signs and symptoms other than those rated by the MNSI, suggesting peripheral nerve involvement, and also because the MNSI is still just a screening test.

Is the Allen's test adequate to safely confirm that a radial artery may be harvested for coronary arterial bypass grafting?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether the Allen's test, plethysmography, Doppler ultrasound or MRI imaging was the best method of assessing the presence of adequate collateral blood flow in the arm preoperatively prior to radial artery harvest for conduits during CABG surgery. Altogether 176 papers were identified using the reported search of which 15 represented the best evidence on the topic. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses were tabulated. We conclude that whilst there are theoretical limitations with the Allen's test, for most patients it is an adequate method of assessing collateral arm flow prior to radial artery harvest and several large studies have confirmed the absence of neurological and vascular adverse outcome with a modified Allen's test cut-off point of up to 12 s. However, if there are concerns about collateral flow then a second confirmatory test such as dynamic Doppler ultrasound or measurement of digital pressure changes with radial artery occlusion can also be used prior to harvest. Newer techniques such as Gadolinium-enhanced magnetic resonance angiography have also been described to confirm adequate collateral circulation prior to radial artery harvest for CABG conduit and whilst in time they might come to represent an ultimate 'gold standard' they are clearly too expensive and impracticable for everyday use.

Establishment of Diagnostic Cutoff Points for Levels of Serum Antibodies to Pertussis Toxin, Filamentous Hemagglutinin, and Fimbriae in Adolescents and Adults in the United States

Numerous reports have documented that serologic methods are much more sensitive than culture for the diagnosis of pertussis in adolescents and adults. However, a standardized serologic test for pertussis is not routinely available to most clinicians, and the serologic test levels or cutoff points correlated with diseases have not been determined. The goal of the present study was to examine the distribution of immunoglobulin G (IgG) levels against three Bordetella pertussis antigens (pertussis toxin [PT], filamentous hemagglutinin [FHA], and fimbria types 2 and 3 [FIM]) and to determine population-based antibody levels for the purpose of establishing such diagnostic cutoff points. Enzyme-linked immunosorbent assays (ELISAs) were performed with sera from >6,000 U.S. residents aged 6 to 49 years who participated in the Third National Health and Nutrition Examination Survey. Mixture models were developed to identify hypothesized exposure groups and establish diagnostic cutoffs. Quantifiable (>20 ELISA units/ml [EU]) anti-FHA and anti-FIM IgG antibodies were common (65 and 62% of individuals, respectively), but quantifiable anti-PT IgG antibodies were less frequent (16%). Given the distributions of antibody levels, an anti-PT IgG level of > or =94 EU was proposed as the diagnostic cutoff point. Application of this cutoff point to culture-confirmed illness in a prior study investigating cough illness yielded a high diagnostic sensitivity (80%) and specificity (93%). A standardized ELISA for anti-PT IgG with a single serum sample appears to be useful for the identification of recent B. pertussis infection in adolescents and adults with cough illness. The PT cutoff point will be further evaluated in prospective studies of confirmed B. pertussis infection.

Fasting and post-glucose load--reference limits for peripheral venous plasma glucose concentration in pregnant women.

Recently both the American Diabetes Organization (ADA) and World Health Organization (WHO) have revised the diagnostic recommendations for gestational diabetes mellitus (GDM), however, they did not not reach agreement on the criteria for diagnosis, the referral criteria for the confirmatory oral glucose tolerance test (OGTT), its standardization, and diagnostic cut-off point. The aims of this study were to investigate if the fasting venous plasma glucose mmol/l (f-vPG) and the 2-hour venous plasma glucose mmol/l (2h-vPG) after a WHO standardized 75 g oral glucose tolerance test (OGTT) in a non-risk group of pregnant women during first and third trimester of pregnancy deviated from that of risk groups, to establish a reference interval for f-vPG and 2h-vPG, and to investigate the predictive role of f-vPG for the 2h-vPG glucose concentration. This is a population-based case-control study where a consecutive number of pregnant women were invited to screening irrespective of their risk factors for GDM. All women filled in a questionnaire of the Danish national screening program on risk factors and had f-vPG and the 2h-vPG measured. By ruling out women with GDM and risk factors, we isolated a non-risk reference class. The In f-vPG parametric 97.5 centile was less than 5% higher during week 32 of pregnancy than during week 20, and therefore these groups were combined. The f-vPG 95% reference interval was from 4.01 mmol/l (95% CI: 3.96 to 4.07 mmol/l) to 5.26 mmol/l (95% CI: 5.19 to 5.34 mmol/l). "The true upper normal limit", the 99.9 centile, was 5.69 mmol/l (95% CI: 5.59 to 5.80 mmol/l). The f-vPG was 0.6 mmol/l lower over the whole range in pregnant women compared to age-matched non-pregnant women. The distribution of 2h-vPG concentrations at week 20 was non-Gaussian and therefore considered non-homogeneous, while it was Gaussian distributed and homogeneous at week 32. The 2h-vPG 95% reference interval of the combined weeks was from 2.80 mmol/l (95% CI: 2.56 to 3.04 mmol/l) to 7.58 mmol/l (95% CI: 7.34 to 7.82 mmol/l), and the upper limit of normal (99.9 centile) was 8.96 mmol/l (95% CI: 8.63 to 9.29 mmol/l). Distributions of f-vPG and 2h-vPG were distinct in our defined risk classes. In individual cases, no systematic correlation was found between the f-vPG concentration at week 20 and week 32. The f-vPG concentrations at any of the weeks did not predict the 2h-vPG level and no single clinical risk factor was decisive for the presence of GDM.

Multilevel Likelihood Ratios for Identifying Exudative Pleural Effusions

To determine multilevel likelihood ratios for pleural fluid tests that are commonly used to discriminate between exudative and transudative pleural effusions. Meta-analysis of patient-level data. Selected studies included patients with diagnoses of exudative or transudative pleural effusions who underwent thoracentesis and laboratory analysis of their pleural fluid. Studies were identified by searching MEDLINE and related bibliographies. Data were obtained for 1,448 patients from seven primary investigators or extracted from dot plots in published reports. Likelihood ratios were calculated from extracted data stratified across ranges of test result values. Sufficient data were available to calculate multilevel likelihood ratios for the elements of Light's criteria (pleural fluid lactate dehydrogenase [LDH], ratio of pleural fluid to serum LDH, and ratio of pleural fluid to serum protein), pleural fluid protein, ratio of pleural fluid to serum cholesterol, pleural fluid cholesterol, and gradient of pleural fluid to serum albumin. Each of these tests provided levels of likelihood ratios through the most clinically relevant range (0 to 10). Multilevel likelihood ratios combined with a clinician's estimation of the pretest probability of an exudative effusion improve the diagnostic accuracy of discriminating between exudative and transudative pleural effusions. Likelihood ratios avoid the use of confusing terms, such as "pseudoexudates," that derive from the use of single cutoff points for pleural fluid tests.

Comparison of test characteristics of urine dipstick and urinalysis at various test cutoff points

Study Objective: We compare the test characteristics of urine dipstick and urinalysis at various test cutoff points in women presenting to emergency departments and an intermediate care center with symptoms of urinary tract infection. Methods: This was a prospective, observational study of adult women presenting to 1 of 2 community hospital EDs or an intermediate care center with dysuria, urgency, or urinary frequency on history, or suprapubic or costovertebral angle tenderness on examination. Patients who had taken antibiotics in the past 72 hours, had indwelling Foley catheters, symptomatic vaginal discharge, diabetes mellitus, immunodeficiency disorders, or were unable to provide a reliable history were excluded. The patient's clean-catch or catheterized urine specimen was tested immediately by a nurse using a Multistix 9 SG reagent strip. A second aliquot was sent within 1 hour of collection to the hospital laboratory, where a semiautomated microscopic urinalysis and a urine culture were performed. A positive urine culture was defined as more than 100,000 colonies of 1 or 2 uropathogenic bacteria per mL of urine at 48 hours. Dipstick and urinalysis data were compared with urine culture results. Sensitivity, specificity, and predictive values were calculated at various definitions of a positive test, or “test cutoff points,” for combinations of leukocyte esterase, nitrite, and blood on dipstick and for RBCs and WBCs on urinalyses. The probability of an erroneous decision to withhold treatment on the basis of a negative test result was defined as “undertreatment,” or 1 minus the negative predictive value. “Overtreatment” was defined as 1 minus the positive predictive value. Results: Three hundred forty-three patients were enrolled in this study. Twelve patients were withdrawn because of missing laboratory results. Forty-six percent (152/331) of patients had positive urine cultures. If urine dipstick results are defined as positive when leukocyte esterase or nitrite is positive or blood is more than trace, the overtreatment rate is 47% (156/331) and the undertreatment rate is 13% (43/331). If urinalysis results are defined as positive when WBCs are more than 3 per high-power field or RBCs are more than 5 per high-power field, the overtreatment rate is 44% (146/331) and the undertreatment rate is 11% (36/331). Matched pairs of test characteristics were identified when the analysis was repeated using more than 10,000 colonies per mL as a positive culture. Conclusion: In this patient population, similar overtreatment and undertreatment rates were identified for various test cutoff points for urine dipstick tests and urinalysis. Although a urine dipstick may be equivalent to a urinalysis for the diagnosis of urinary tract infection, the limitations in the diagnostic accuracy of both tests should be incorporated into medical decisionmaking. [Lammers RL, Gibson S, Kovacs D, Sears W, Strachan G. Comparison of test characteristics of urine dipstick and urinalysis at various test cutoff points. Ann Emerg Med. November 2001;38:505-512.]

Sensitivity and specificity of carbohydrate-deficient transferrin in drinking experiments and different patients

Information provided by patients about the amounts of alcohol they drink may often be too subjective and therefore unreliable. Because of the possible serious consequences of interactions between alcohol and medication, reliable laboratory test markers for alcohol consumption are needed. Carbohydrate-deficient transferrin (CDT) is at present the best available objective measure of drinking behavior. During a withdrawal trial, 92 alcohol-dependent patients who had been admitted to a hospital in an ethanol-intoxicated state were monitored over the following 28 days by using the percent carbohydrate-deficient transferrin (%CDT of total transferrin) (%CDT) method. At the time of admission, 63% showed elevated %CDT levels. After a subsequent period of abstinence, a decrease in %CDT levels was apparent in four different groups of patients, whereas in two groups, comprising the greatest number of patients, normal %CDT levels were evident after 14 days of abstinence. In patients whose CDT levels were very high at study initiation, it took at least 21 to 28 days—and sometimes longer—for CDT to decrease to the radioimmunoassay (RIA) %CDT test cutoff point of 2.5. In a further study of 56 male alcohol-dependent patients, we measured liver enzyme concentrations, mean corpuscular volume (MCV), and four CDT variants on the first day of evidence of withdrawal syndrome. We found a significant correlation between results on the Munich Alcoholism Test (MALT) and MCV levels; among gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels; and among all four CDT variants. A cluster analysis yielded three clusters: (1) GGT, AST, and ALT levels; (2) MCV levels and MALT results; and (3) all CDT measurement variants. We conclude that these three clusters measure different detriments to the patient and that all available CDT variants are commensurate.