Anne-MariePKU is the test’s name. That covers a range of conditions that they are testing for though from what I could understand. Not just PKU which is Phenylketonuria is it not?
It looks to me like Birth Weight and Gestational Age can affect the test results. See below. Is the cut off limit 30nmol/L. Also don’t forget the blood spot is more concentrated whole blood not blood with plasma in. I see the results here in nmol/L though. But 30nmol/L appears to be within the normal ranges when we speak in terms of testing children who have CAH because children who do not have CAH do not have the same ranges applied to them. In CAH the kid’s bloods allowed to be somewhat higher than what they would be in a normal child. Perhaps that is why they think 45 is high?
ABSTRACT FROM PUB MED:
Neonatal screening program for congenital adrenal hyperplasia: adjustments to the recall protocol.
Gruneiro-Papendieck L, Prieto L, Chiesa A, Bengolea S, Bossi G, Bergada C.
Fundacion de Endocrinologia Infantil, Centro de Investigaciones Endocrinologicas CEDIE, Division de Endocrinologia Hospital de Ninos R. Gutierrez, Capital Federal, Argentina. protir@cedie.guti.gov.ar
OBJECTIVE: To evaluate the influence of gestational age (GA) and birth weight (BW) on 17 alpha-OH-progesterone (17-OHP) levels with respect to their impact on the recall rate of neonatal screening programs for congenital adrenal hyperplasia (CAH). PATIENTS AND METHODS: In June 1997 we began a pilot screening program for CAH measuring 17-OHP using a fluoroimmunoassay method (DELFIA) on dried blood spots. Until September 1999, 24,153 babies were screened. Among them, we analyzed the levels of 17-OHP in 1,313 samples from healthy preterm babies (23-36 weeks) and 1,500 term babies (>37 weeks), grouped according to GA and BW. All preterm babies underwent another sampling in their 2nd week of life. RESULTS: 5 CAHs were detected. The 30-nmol/l cutoff limit for 17-OHP in blood corresponded to the calculated 99th percentile in term newborns, while in preterm babies higher levels were found. GA and BW correlated inversely with 17-OHP levels. CONCLUSION: GA and BW were useful tools to adjust cutoff levels, obtaining a significant reduction in follow-up testing and psychological stress for families. The high false-positive recall rate in preterm babies can be substantially lowered with adjusted GA and/or BW criteria. Copyright 2002 S. Karger AG, Basel
PMID: 11805430 [PubMed - indexed for MEDLINE]