Using immunoradiornetric TSH assay （TSH-IRMA） to measure whole blood TSH levels spotted onto filter paper

we compared TSH levels among different age groups （neonates

<1 yr infants

schoolchildren aged 7 to 14 yrs

adults

pregnant women and reproductive-age women） in Guiyang

where iodine deficiency has long been a problem. The results showed: 1) The percentage of subjects with TSH levels equal to or greater than 5 mIU/L in the neonate group was 38.9% while the percentages in the other groups were 0-3.3% （P<0.01）; 2)The TSH levels of the neonates were inversely related to the urinary iodine values of their mothers （pregnant women）. （r=-0. 5

P<0. 01）;3)97.6% of the inhabitants in Guiyang ingested salt with less than 20mg/kg iodine. The results indicate that iodine deficiency remains a problem in Guiyang. Neonates are the only ideal population for monitoring iodine deficiency.