Method/Procedure: Incubate 1 dry spot 4.25mm + 100ul 125-t4-derivative (which does not bind to TBG) + 100 ul solidphase antibody for 1h/37°C.Add 2.5ml aqua dest., centrifuge 15 min., discard supernatant, count precipitate for 1 min. Standard Preparation: powdered standards are solved in lml heparin-blood free of T4 (Hkt 50%) and dried on filterpaper. Results: Measurable range 20-520pgFT4/ml blood. Interassay C.V. 10%. Clinical study: Dry spot specimens of 3000 newborns(day 5) and 100 babies (aged 2-4 months) were evaluated for TSH and FT4. Results: Healthy mature newborns mean 115pgFT4/ml;SD 40 pg/ml.CUT OFF (2SD) 30 pg/ml; RECALLRATE 0.9% (TSH 0.7%).Healthy babies:98pg/ml (SD 40pg/ml). Prematures:significantly lower mean than in matures. Sick newborns (RDS, sepsis, etc) TSH-values were not different to the healthy group, but FT4 was lower than 20pg/ml in more than 10%. Priimary hypthyroidism:Four newborns with prim.h. had TSH higher than 100uU/ml and FT4 was lower than 20 pg/ml. Conclusions: Screening for hypothyroidism in healthy mature newborns FT4-evaluation is equal to TSH with the advantage of getting results on the same day. In sick newborns FT4 as a single parameter is not dianostic for hypothyroidism. Maybe it is prognostic, because normalising of FT4 is parallel to progress of clinical status.Ref: S. Zabransky extr. paed. (Berlin) 7(1):25–27 (1983)
展开▼
