Accuracy In Pregnancy Research Articles

A Brief Depression Screening Tool for Perinatal Clinical Practice: The Performance of the PHQ-2 Compared with the PHQ-9.

There is ongoing interest in using brief screening instruments to identify perinatal depression in clinical practice. One ultra-brief screening instrument for depression is the Patient Health Questionnaire-2 (PHQ-2), but thus far its accuracy in perinatal clinical practice has been barely researched. In the present study, we aimed to assess the screening accuracy of the PHQ-2 against the Patient Health Questionnaire-9 (PHQ-9) in a large sample of perinatal women. A total of 1155 consecutive women attending 11 health care centers throughout Italy completed the PHQ-9 (which includes the PHQ-2) during pregnancy (27-40 weeks) or postpartum (1-13 weeks). Sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio positive, likelihood ratio negative, and overall accuracy were calculated using cut points 3 or greater and 2 or greater. During pregnancy, PHQ-2 greater than or equal to 3 revealed low sensitivity (38.4%-44.7%) but high specificity (97.8%-99.3%). In postpartum, it revealed moderate sensitivity (56.9%-70.6%), high specificity (95.8%-99.8%), and fair overall accuracy in pregnancy (70%). The alternative threshold greater than or equal to 2 revealed very high sensitivity (pregnancy: 92.1%-95.2%; postpartum: 87.1%-95.2%), moderate specificity (pregnancy: 78.1%-83.2%; postpartum: 68.8%-81.1%) and good overall accuracy, both during pregnancy (87%) and postpartum (84%). The PHQ-2 provided acceptable accuracy for screening for depression compared with the PHQ-9. In perinatal screening practice, a threshold of 2 or greater should be preferred as this ensures high sensitivity, missing only approximately 6% to 8% of cases, and a false-positive rate (percentage of women classified as affected with depressive symptoms when they are not) of 19% to 25%.

Improving diagnostic accuracy in pregnancy with individualised, gestational age-specific reference intervals

Background and aimsInvestigations in pregnancy should be interpreted using pregnancy-specific reference intervals (RIs). However, because of the progressive nature of pregnancy, even pregnancy-specific RIs may not be equally representative at different gestations. We proposed that gestational age-specific RIs may increase diagnostic accuracy over those with fixed limits. Materials and methodsThe trajectory of platelets was mapped in 32,778 pregnant women, using 116,798 results. Then we evaluated the accuracy with which a low measurement in early pregnancy (<3rd centile) predicted thrombocytopaenia at term, compared to the existing limit (<150 × 109/L). ResultsPlatelets fell by 14.8% between 8 and 40 weeks. Platelets below the 3rd centile before 20 weeks predicted thrombocytopaenia at term (<100 × 109/L) with a significantly greater degree of accuracy than a fixed limit (AUC 0.86 vs. 0.76, p = 0.004). ConclusionPregnancy-specific RIs can be defined using routinely collected hospital data, and the abundance of such freely available data enables a detailed investigation of temporal changes throughout gestation. Individualised RIs offer improved accuracy profiles, over and above those already derived specifically from pregnant populations. Clinicians should consider how this may be used to improve diagnostic accuracy for biomarkers used in current clinical practice, and those yet to be defined.

An inaccurate automated device negatively impacts the diagnosis and treatment of gestational hypertension.

Automated blood pressure devices are frequently introduced in maternity care without prior validation for their accuracy in pregnancy. Our objectives were to, firstly, establish the accuracy in pregnancy of a locally used device (Welch Allyn 300) and, secondly, to audit its impact on the diagnosis and treatment of hypertension. Validation study: The device was evaluated using the grading criteria of the European Society of Hypertension International Protocol (ESH-IP) (2010). Two observers took nine same-arm measurements alternating between the Welch Allyn and the mercury sphygmomanometer. Thirty-three women of any gestation were included. Clinical audit: One observer took three same-arm measurements alternating between the Welch Allyn and the mercury sphygmomanometer. One hundred women of any gestation referred with suspected hypertension were included. The main outcome measures were the proportion diagnosed with hypertension or commenced on anti-hypertensive treatment on the presenting visit when using either the manual or the automated device. Grading criteria of the ESH-IP (2010) and proportion of women diagnosed with hypertension or commenced on antihypertensive therapy at the presenting visit when using either manual sphygmomanometry or the Welch Allyn device. The Welch Allyn 300 series failed to meet the criteria of the ESH-IP (2010) for pregnancy. Compared to the mercury device, it under diagnosed hypertension by 48% and need for treatment by 80%. The Welch Allyn 300 cannot be recommended for the measurement of blood pressure in pregnancy. Its use leads to the under-diagnosis and under-treatment of gestational hypertension.

PFM.07 Quantitative fetal fibronectin testing as a predictor of spontaneous preterm delivery after cervical surgery

IntroductionQuantitative fetal fibronectin (qfFN) testing has demonstrated accuracy at predicting sPTB in high-risk asymptomatic women (previous preterm birth or late miscarriage). It is not known whether qfFN has predictive accuracy...

Methods of assessing renal function

Accurate assessment of renal function is critical for appropriate drug dosing of renally excreted compounds. Glomerular filtration rate (GFR) is considered the best marker of kidney function. Inulin clearance forms the gold standard for measuring GFR, both in adults and in children. The method is invasive, cumbersome, and smaller children require urinary catheterization for accurate timed urine collections. Nuclear medicine methods replaced inulin clearance in the 1970s after (51)Cr EDTA clearance was introduced. Inulin has no plasma protein binding, whereas all commonly used radioisotopes have a small amount of plasma protein binding that leads to lower values. Only iohexol does not have significant plasma protein binding. The underestimation due to plasma protein binding is partially offset by overestimation due to the use of non-compartmental pharmacokinetic modeling of the plasma disappearance of the radioisotope. The problem could be overcome with a urinary nuclear medicine clearance method, but these have not been validated in children. Endogenous markers of GFR include serum creatinine and low molecular weight proteins such as cystatin C and beta-trace protein. Of these, estimation of GFR using cystatin C appears to be the most promising, although its accuracy in pregnancy and in the neonatal period may be limited.

Field Evaluation of Diagnostic Accuracy of an Oral Fluid Rapid Test for HIV, Tested at Point-of-Service Sites in Rural Zimbabwe

The objective of this study was to validate the use of OraQuick ADVANCE Rapid HIV-1/2 Antibody test (OraSure Technologies Inc., Bethlehem, PA) on oral fluid for a population-based HIV prevalence survey of rural youth in southeast Zimbabwe. The evaluation was conducted in patients presenting for voluntary counseling and testing at rural clinics. Each participant provided an oral fluid sample tested using OraQuick ADVANCE. In addition, dried blood specimens were collected and tested blind at the National Microbiology Reference Laboratory in Harare using two enzyme-linked immunosorbent assays (ELISA; Vironostika, Biomérieux BV, Boxtel, The Netherlands and Ani Labsystems, Ltd., Vantaa, Finland) with confirmatory Western blot (MP Diagnostics [formerly Genelabs Diagnostics], Medical Technology Promedt Consulting GMBH, St. Ingbert, Germany) for samples with discrepant results. Diagnostic accuracy of the oral fluid assay was determined against the ELISA/Western blot algorithm as gold standard. Five hundred and ninety-one participants took part in the study between February and July 2006. Sensitivity of the test on oral fluid was 100% (95% confidence interval [CI]: 97.9-100), and specificity was 100% (95% CI: 99.1-100). HIV prevalence based on the reference standard was 29.8% (95% CI: 26.1-33.5). This is one of the first validations of this rapid assay on oral fluid conducted in a general population to be reported in Africa. While there are some limitations with the assay (e.g., unlikely to detect those in early stages of HIV infection or with reduced viral load; altered accuracy in pregnancy) these limitations also apply to other rapid assays. The results showed the assay to be 100% accurate in determining HIV status, performed well in field settings, and can be considered suitable for use in epidemiologic surveys aiming to estimate HIV prevalence in general populations.