[Evaluation of TSH cutoff value in blood-spot samples in neonatal screening for the diagnosis of congenital hypothyroidism in the Programa "Primeiros Passos" - IEDE/RJ].

Objective: To analyze the confirmed or not-confirmed cases of neonatal screening (CH) screened in the Programa "Primeiros Passos", stratifying them into TSH blood-spot (TSH-BS) ranges.

Materials And Methods: To stratify, in ranges of TSH-BS as a function of TSH serum (TSH-S), the cases called for a confirmatory test from January, 2006 to July, 2009.

Results: Around 37% of the confirmed cases (475) showed TSH-F > 9.5 mUi/L, but most of the confirmed cases were in lower TSH-F ranges. Among the unconfirmed cases (4,613), most were found in the lower ranges. There was no TSH-F range exclusive to unconfirmed cases.

Conclusion: TSH-BS cutoff value used is crucial in the diagnosis of CH and should be low, even if more confirmatory tests are performed. More studies are needed to determine the best cutoff value of TSH-BS for neonatal screening.