AbnormallyHigh Concentrationsof p2-Microglobulinin Acquired immunodeficiencySyndrome(AIDS) Patients

1560 CLINICAL CHEMISTRY, Vol. 29, No. 8, 1983 universal phenylketonuria/hypothyroidism screen. The project was based on an hypothesis first outlined by Crossley et al. (1), viz., that an abnormally high blood IRT value for a newborn is suggestive of cystic fibrosis (CF). Details of the methods were previously described (2). We tested 25 000 newborns and identified seven infants confirmed to have CF. One of the seven was not detected in the initial assay, but a repeat card, taken one week later because the infant was premature (birth weight, 1086 g), revealed an increased value for IRT. Values for all affected infants were within the top 1% of each assay run of 200 specimens. During the project period, eight infants were diagnosed with CF. The one not detected by the IRT program did not have a filter paper card taken at birth. From our experience, we conclude that the IRT test is a reliable indicator of infants with CF if the reagents used are of good quality and the specimens are fresh. We would use only reagents comparable to those outlined by Crossley et al. (3) and would assay the specimens within a few days of their arrival at the screening laboratory.