This article is more than 5 years old. Information may no longer be current.
Ethnicity affects TSH screening in UK newborns
Click Here to Manage Email Alerts
Blood spot data from more than 800,000 newborns in the United Kingdom suggest mean thyroid-stimulating hormone levels in this population vary by ethnicity, according to recently published results, prompting researchers to recommend that health care providers consider ethnic diversity when setting a cutoff thyroid-stimulating hormone level in screening for congenital hypothyroidism.
“There is a lack of evidence to assess the optimal lower cutoff point in terms of screening sensitivity and specificity,” Catherine Peters, MRCP, FRCPCH, MD, of the Great Ormond Street Hospital in London, and colleagues wrote. “In addition, UK children vary between regions in terms of ethnicity and iodine sufficiency, which may also influence the optimal cutoff value.”
Researchers in London studied blood spot tests from 824,588 babies screened for congenital hypothyroidism at the Great Ormond Street Hospital Newborn Blood Spot Screening Laboratory between 2006 and 2012. Peters and colleagues noted the hospital’s current procedure calls for newborns with a TSH level between 6 mU/L and 19.9 mU/L to receive a second test 1 week after the initial screening, whereas babies whose TSH levels exceed 20 mU/L are automatically referred for clinical testing. There is no national standard cutoff level in the United Kingdom or internationally, however.
The researchers examined several cutoff points between 4 mU/L and 10 mU/L, and found that the number of samples that exceeded the 4 mU/L cutoff increased over time (P < .0001); this was not true at cutoff points of 6 mU/L or 10 mU/L (P > .1). When examining ethnicity, they found that regardless of cutoff point, white newborns were least likely to exceed the cutoff (OR = 1). However, Pakistani and Bangladeshi newborns were more likely (OR > 2), and Chinese newborns were the most likely (OR > 3.5) to exceed the cutoff. Peters and colleagues concluded that, based on a sampling of babies representative of the London population, “the best cutoff to use would be either 6 mU/L or 8 mU/L.”
“However, this large dataset from a single center based in an ethnically diverse city provides new insights into the effects of ethnicity on screening TSH concentrations, and this also needs to be considered when setting cutoff points,” the researchers wrote. – by Andy Polhamus
Disclosure: The researchers report no relevant financial disclosures.
Click Here to Manage Email Alerts