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A simple and reliable method of paired TSH assay was developed and used in screening for neonatal primary hypothyroidism. In this method, a paired assay is first done. Equal parts of the extracts of dried blood spots on filter paper (9 mm diameter) from two infants 4-7 days old are combined and assayed for TSH by double antibody RIA. If the value obtained is over the cut-off point, the extracts are assayed separately for TSH in a second assay to identify the abnormal sample. Two systems, A and B, with different cut-off points were tested. On the basis of reference blood samples (serum levels of TSH, 80 microU/ml in system A and 40 microU/ml in system B), the cut-off point was selected as follows: upper 5 (A) or 4 (B) percentile in the paired assay and values of reference blood samples in the second individual assay. Four cases (2 in A and 2 in B) of neonatal primary hypothyroidism were found among 25 infants (23 in A and 2 in B) who were recalled from a general population 41,400 infants (24,200 in A and 17,200 in B) by 22,700 assays. This paired TSH neonatal hypothyroidism.

We have simultaneously measured T4 and TSH concentrations from 93,000 consecutive filter paper blood samples received by the Quebec network for Genetic Medicine. T4 was measured using the Micromedic Automated System and TSH was measured by RIA kits from Pharmacia and Becton Dickinson, each for a 6-month period. Statistical analyses to assess quality control parameters for the various methods revealed that the T4 assay had greater precision and reproducibility than either of the 2 commercially available TSH kits. The number of false negative results was similar for both methods. Eight infants with ectopic thyroid glands were correctly detected by the T4 method. One infant with secondary hypothyroidism was detected by the T4 approach and missed by the TSH methodology. Three infants overall would have been missed using either the T4 or TSH approach. These data indicate that primary T4 screening has similar sensitivity compared to TSH kits for mass screening programs for congenital hypothyroidism.

A pilot newborn screening program for 21-hydroxylase deficiency congenital adrenal hyperplasia (CAH) was conducted in Alaska using a 3-mm disc filter paper elution technique of capillary whole blood for 17-hydroxyprogesterone (17-OHP) by RIA. The filter paper specimens were provided via the mandated newborn screening program. The highest values of 17-OHP in a control population of 4569 consecutive normal neonates, aged 2–14 days, was 40 pg/disc, and the range of values for 20 newborns with proven CAH was 57–980 pg/disc. All Alaskan newborns with 17-OHP levels of 57 pg/disc or greater were referred for diagnostic workup, and initially, those with 17-OHP levels of 41–56 pg/disc were recalled for a second specimen. However, the range for recall was changed subsequently to the 17-OHP level greater than 51 pg/disc, since no newborns with 17-OHP level below 50 pg/disc were found to be affected in the initial screening. In a 30-month period, the Alaskan newborns screened on the third day of life consisted of a t...

The method of Haber for the purification of (125I)-labeled angiotensin by high volt age paper electrophoresis has been modified. Instead of eluting the labeled peptide from the paper in a single bulk elution, serial small elutions are collected, resulting in a highly purified product in later elutions.