Do general practitioners use thyroid stimulating hormone assay for opportunistic screening?
OBJECTIVE
The presenting features of early thyroid disease can be subtle and non-specific; consequently, general practitioners (GPs) have a low threshold for ordering thyroid function tests (TFTs). This study examined the use and results of TFTs by GPs in a 1-year period in a population-based sample of adults without known thyroid disease enrolled in general practice.


METHODS
This record linkage study analysed the use of TFTs over a 12-month period from laboratory data, which were linked to patient's GP records from two large urban New Zealand general practices with a total registered population of 21,290 patients. Outcomes were analysed by age and gender.


RESULTS
One in six adult patients visiting their GP in a 12-month period had a thyroid stimulating hormone (TSH) test, whilst only 1 in 20 had a free thyroxine (FT4) test. 7.0% had an elevated TSH concentration and 1.0% had a low TSH concentration, most with subclinical disease. Rate of testing was higher in females compared with males.


CONCLUSIONS
This study suggests that general practitioners are opportunistically screening with TSH alone to find new cases of thyroid disease.
Gibbons
Veronique
V
Waikato Clinical School, Waikato Hospital, Hamilton, New Zealand. gibbonsv@waikatodhb.govt.nz
Lillis
Steven
S
Conaglen
John V
JV
Lawrenson
Ross
R
D000328:Adult; D001291:Attitude of Health Personnel; D005194:Family Practice / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data*; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D013959:Thyroid Diseases / Q000097:blood / Q000175:diagnosis*; D013960:Thyroid Function Tests / Q000706:statistics & numerical data*; D013972:Thyrotropin / Q000097:blood; D014505:Urban Population / Q000706:statistics & numerical data; D055815:Young Adult
D013972:Thyrotropin