108 LARSENetal. TABLE IV. BASELINE SERUM TSH CONCENTRATIONS AND RESPONSE TO 500 pg THYROTROPIN RELEASING HORMONE(TRH) IN CONTROL MARSHALLESE SUBJECTS Mean + SD pU/ml Basal TSH Mean + SD 2.0 + 0,73 Range 0.5 - 3.0 TSH 20 min after TRH 11.5 +£4.5 Range 4.7 — 20 TABLE V. CRITERIA FOR THE DIAGNOSIS OF BIOCHEMICAL THYROID DYSFUNCTION 1. Basal plasma TSH > SpU/ml on two occasions > 3 yU/ml . on two occasions or 2. a. Basal plasma TSH b. Plasma TSH after TRH > 22 pU/ml TABLE VI. FREQUENCYOF AT LEAST A SINGLE ELEVATED BASAL SERUM TSH CONCENTRATION IN THE MARSHALLESE POPULATION Number Number 9, 115 1] 10 Utirik exposed (Thyroid dose < 95 rads) 99 12 12 Rongelap and Ailingnae exposed (Subjects without surgery and excluding Nos 3 & 5) 43 1] 26 tested Control unexposed > 3.0 nU/ml