CONGENITAL ADRENAL-HYPERPLASIA AND EARLY NEWBORN SCREENING - 17-ALPHA-HYDROXYPROGESTERONE (17-ALPHA-OHP) DURING THE FIRST DAYS OF LIFE

Objective-Definition of upper limits for 17 alpha-hydroxyprogesterone (17 alpha-OHP) is important as its measurement is used in screening fo r congenital adrenal hyperplasia. This study aimed at investigating th e cut off concentrations in relation to the day of sample collection. Methods-17 alpha-OHP concentration was determined in dried filter pape r blood spots taken from cord blood and by heel pricking up to the six th day of life. A sensitive fluoroimmunoassay (DELFIA) method was used . Samples from 1091 apparently healthy full term neonates were tested. Samples were separated according to the age of sampling. Results-The 17 alpha-OHP (nmol/l blood) (median and 97.5th centile) concentrations according to the age of sampling were: cord blood (n=126) 123.7, 265. 6; first day 0-6 hours (n=30) 49.4, 80.3; 6-12 hours (n=57) 42.7, 79.8 ; 12-18 hours (n=58) 38.1, 62.7; 18-24 hours (n=67) 28.8, 49.7; second day 24-36 hours (n=51) 23.6, 43.3; 36-38 hours (n=63) 19.9, 35.4; thi rd day (n=200) 10.6, 23.5; fourth day (n=197) 8.8, 20.8; fifth day (n= 76) 6.4, 18.3; sixth day (n=166) 6.6, 19.4. Conclusion-Cord 17a-OHP co ncentrations were very high as previously described, probably owing to steroid production by fetal adrenal glands. Therefore, cord blood is not useful for screening purposes. Thereafter there is a gradual decli ne in 17a-OHP median concentrations. A cut off value of 30 nmol/l bloo d was useful in samples obtained after 48 hours of life. However, cut off values before 48 hours should be adjusted according to the samplin g time.