Patterns of add-on tests for hospitalized and for private patient populations.

Context: The policy of storing clinical samples in a pathology laboratory is based on long-standing practice rather than on objective data regarding the actual use of the stored samples.

Objective: To determine the time after initial order that requests for add-on tests are submitted to the laboratory. These data might be useful for improving the efficiency of sample storage.

Reducing substances in urine: a paradigm for changes in a standard test.

Detection of reducing substances in urine has been a standard laboratory procedure for about 50 yr. It is used as a screening test for inborn errors of carbohydrate metabolism. Although the test has poor specificity and most states perform mandatory newborn screening for the common genetic defects, most clinical laboratories still perform this as a reflex test on all pediatric urine samples.

Performance of a new-generation chemiluminescent assay for hepatitis B surface antigen.

Background: The usual criteria for analysis of hepatitis B surface antigen (HBsAg) are detection of HBsAg and result confirmation by antibody neutralization. We observed that with the Immulite 2000 HBsAg assay [Diagnostics Product Corporation (DPC)] a relatively high percentage of weakly reactive (WR) samples did not pass the neutralization step.

Methods: For each of 3 lots of Immulite 2000 HBsAg reagent (DPC), we collected and analyzed HBsAg data from approximately 3000 to 4000 patient blood samples and compared these data with HBsAg data from 3393 samples tested with the Abbott Auszyme assay.

Predicting respiratory distress syndrome using gestational age and fetal lung maturity by fluorescent polarization.

Objective: This study was undertaken to design a predictive model for assessing the risk of developing respiratory distress syndrome (RDS) by using gestational age (GA) and results from a quantitative fluorescence polarization-based fetal lung maturity assay (TDx FLM II).

Study Design: The study populations from the 3 largest published studies analyzing the association between TDx-FLM II and the development of RDS were combined for this analysis. A total of 509 patients were included in this study; 57 gave birth to infants who had RDS develop, and 452 gave birth to infants who were unaffected.

Prediction of respiratory distress syndrome using the Abbott FLM-II amniotic fluid assay.

Background: Most laboratories using the Abbott FLM-II assay for assessing fetal lung maturity follow the manufacturer's recommendations for interpreting the surfactant to albumin ratio (S/A). Thus, values >55 mg/g are considered mature and values <40 mg/g, immature-leaving a wide range of indeterminate values. Little data is available to assist the clinician in interpreting values between 40 and 55 mg/g.