Results of a regional cord blood screening programme for detecting neonatal hypothyroidism.

Abstract

SUMMARY Our regional cord blood screening programme for detecting neonatal hypothyroidism using initial cord blood thyroxine (T4) determinations, with supplemental thyrotropin (TSH), and triiodothyronine resin uptake (T3U) measurements, gave an incidence of thyroid abnormalities of 1/3000 births, with 115000 infants having severe primary hypothyroidism. No hypothyroid infant detected in the programme had been suspected clinically before the screening and, in retrospect, only a few babies had any signs of hypothyroidism. Supplemental TSH and T3U determinations were required on 8-12 % of the population screened initially with a T4 test to avoid missing affected cases. With an initial T4 and supplementary TSH and T3U testing on cord blood serum, recalls to exclude primary hypothyroidism were reduced to 0-16 % of the screened population. The incidence of abnormalities detected in this cord blood screening programme was comparable with that reported by others using neonatal dried blood screening methods, indicating that cord blood screening can be effective provided the appropriate recall criteria and transport conditions are used. Nevertheless, for several practical reasons, neonatal dried blood methods are recommended as the screening test of choice for surveying large populations over extensive geographical areas.

Neonatal Screening for Congenital Hypothyroidism in Riyadh: Analysis of Six Years' Experience

“…1,6,13,14,19 In accordance with other reports, thyroid ectopy was the most common. 11,13,[18][19][20] Furthermore, the finding of a high percentage (26%) of patients with normally located glands and high uptake, which suggests dyshormonogenesis, confirms the previous observation of the high incidence in this part of the world.…”

“…As in other studies, clinical signs of hypothyroidism were absent in the majority of our patients and were more obvious in patients with thyroid aplasia 10,11,13,14,18 Therefore, it is apparent that although many infants with aplasia of the thyroid will be detected within the first few weeks of life, on the basis of clinical history and examination, many cases will be missed, especially infants with ectopic glands, as they have some residual tissue that is capable of producing thyroxine in amounts that mask the clinical symptoms and delay the diagnosis. This is supported by the biochemical values of TSH and T 4 in our series (Table 4).…”

“…We found the incidence of confirmed infants with CH in our series, 1:3417, to be comparable to what has been reported by Abu-Osba et al 4 from the Eastern Province of Saudi Arabia and consistent with other reports from Europe and North America. 1,[10][11][12][13][14] However, if we consider infants with positive cord screening in whom confirmation was not possible, the incidence will be even higher at 1:2836. This supports our previous pilot study results 6 and is similar to the Bacchus et al 2 and Majeed-Saidan et al 5 experience at Riyadh Al Kharj Military Hospital program.…”

“…Our protocol showed an acceptable recall rate and proved to be cost effective. 6,[10][11][12][13][14][15] Furthermore, our experience has since shown that the successful implementation of any screening program depends not only on the efficient and comprehensive collection of specimens, transport and laboratory processing but also on access to patients to ensure prompt recall for further testing and therapy. 1,4,6 Variable degrees of enthusiasm among medical teams, difficulties in locating suspicious cases with occasional lack of addresses and telephone numbers, and poor compliance from parents are among the difficulties.…”

Enzyme immunoassay of thyroxine in serum and dried blood samples on filter paper.

“…A specific and sensitive radioimmunoassay (RIA) of thyroxine (T4) is available (Chopra, 1972), which has been widely used in clinical diagnosis of various thyroid disorders and in mass screening for neonatal hypothyroidism (Dussault et al, 1978;LaFranchi et al, 1979;Walfish et al, 1979). But this method involves radiation hazards, and the radioisotopes used have short half times and are expensive.…”