Introduction: The ideal TSH filter value (TSHf) in the neonatal screening tests for Congenital hypothyroidism (CH) is worldwide controversial. Local cutoff point of TSHf was 9.0 mIU/L until recently. OBJECTIVE: To evaluate the clinical and laboratory characteristics of newborns with CH (confirmatory serum TSH > 10 mIU/L) after a lower TSH cutoff. METHODS: Cross-sectional study using data from Neonatal Screening Reference Center of State Rio Grande do Sul, 2018. All cases with TSHf ≥ 6.0 mIU/L were evaluated. A second filter test was performed if the first one (TSH1) was between 6 and 9.0 mIU/L. Newborns with a second TSH filter (TSH2) above 6 mIU/L were called up for confirmatory tests and clinical evaluation. RESULTS: Of the 106,594 screening tests, 244 (0.22%) resulted in TSHf ≥ 6.0 mIU/L. Patients with TSHf1 > 9.0 mIU/L [58 (24%)], were called up for immediate confirmatory tests; patients with TSHf1 6-9.0 mIU/L, [186 (76%)], were submitted to a second filter test (TSHf2). Of these, 153 (82.25%) were discharged after TSHf2 < 6.0 mUI/L. Patients with TSHf2 > 6 mUI/L (21 cases) were referred for consultation. Twelve cases did not perform the second test and were not included. The incidence of altered tests was 7: 10,000 (95% CI: 6-9). The cases were classified by group (G) was: G1: TSHf1 and TSHf2 > 6.0 and < 9.0 mIU/L [11 (13.9%)]; G2: TSHf1 > 6.0 and < 9.0mIU/L and TSHf2 > 9.0 mIU/L [10 (12.7%)]; G3: TSHf1 > 9.0 mIU/L [58 (73.4%)]. The cases of CH (serum TSH > 10 mIU/L) were 9 (81.8%), 10 (100%), 33 (58.9%) in G1, G2 and G3 respectively. The prevalence of CH was 1:2000. Consanguinity, gestational thyroid disease and presence of congenital malformations were more prevalent in G1, Drug addiction and and genetic syndromes were more present in G2. CONCLUSION: The new cutoff point identified about 19 patients/year. This cases would no longer be diagnosed early if the previously established cutoff point was sustained. Despite the small number of patients studied and a short period of evaluation, these results support the new cutoff proposal. Furthermore, the presence of consanguinity, malformations and/or syndromes in the groups with TSH filter of lower cutoff points draws attention to the possibility of a diagnosis of CH.
19 Sep 2019 - 21 Sep 2019