Diagnostic effectiveness of TSH screening and of T4 with secondary TSH screening for newborn congenital hypothyroidism.

We used a receiver operating characteristic (ROC) plot to evaluate the diagnostic accuracy of primary thyrotropin (TSH) screening, and compared it to the primary thyroxine (T4) with secondary TSH screening (T4/TSH) on a certain percentage of the lowest T4 value for newborn congenital hypothyroidism (CH). There were 2198 normal and 117 abnormal CH cases evaluated using both the Wallac Delfia neonatal TSH and neonatal T4 kits. The ROC areas of the primary TSH screening and T4/TSH screening were 0.

Receiver operating characteristic plots to evaluate Guthrie, Wallac, and Isolab phenylalanine kit performance for newborn phenylketonuria screening.

We used ROC plots to evaluate the clinical performance of the Guthrie, Wallac, and Isolab assays for newborn phenylketonuria (PKU) screening and assessed the screening discriminatory power of these three assays by the area under the ROC plot, Youden's J index, and the likelihood ratio. The use of these plots not only allows us to pinpoint the exact cutoff value in screening, but also provides a direct comparison of these three different assays in clinical outcome performance. The optimum cutoff for the newborn PKU screening is a blood phenylalanine concentration of 0.

Newborn phenylketonuria (PKU) Guthrie (BIA) screening and early hospital discharge.

Recent policies of early discharge of postpartum mothers and their infants has raised concerns of possible decreased sensitivity in Guthrie bacterial inhibition assay (BIA) phenylketonuria (PKU) screening resulting in missed cases. In order to assess the potential impact of early discharge from hospital on neonatal screening for PKU and its variants, we performed 18 standard BIA screening tests on 11 newborn infants with the disease. Blood spot samples were collected from 1 to 24 h after birth and were analyzed at the Ontario Ministry of Health newborn screening laboratory according to the routine screening protocol.

Rapid Zeeman atomic absorption determination of copper in serum and urine.

In this simple, quick procedure for determining copper in human serum and urine, the serum and urine specimens were analyzed directly after dilution with a solution of HNO3 and Triton X-100, 1 mL/L each. We calibrated with aqueous standards for quantitation in Zeeman background atomic absorption spectrometry. By modifying the drying and pyrolysis stages of the graphite furnace atomic absorption spectrometer, we reduced the analytical time to 30 s per determination.