Commentary

Refining Diagnostic Precision: The Impact of Race in Clinical Labs

  • By Kurt Miceli, MD
  • July 7, 2025

Samantha Anderer’s Medical News in Brief, Thyroid Disease May be Overdiagnosed, Study Finds, recounted an article in the Annals of Internal Medicine which found that variables, including race, may significantly influence thyroid hormone levels and affect diagnostic accuracy.[1],[2] 

Compared to current laboratory reference values, the distribution of thyroid disease diagnosis greatly changed when accounting for race. According to the Annals article, 50.1% of whites diagnosed with subclinical hypothyroidism under current standards moved to the normal category once age-, sex-, and race-specific reference intervals were considered. For blacks, it was 14%. Moreover, for blacks, 60% moved from the subclinical hyperthyroidism to normal. The same was true for 17.3% of whites under an age-, sex-, and race-specific reference range.[3] 

The authors concluded: “These findings should help establish more accurate reference intervals for thyroid disease […].”[4] If correct, then a change in parameters partly based on race would improve diagnostic precision, minimize unnecessary treatment, and lower avoidable healthcare costs.

This appeal to accuracy in diagnosis comes in contrast to the debate over estimated glomerular filtration rate (eGFR). In that setting a race correction was called “race-based medicine” given race’s “social construct.”[5] Yet, have we sacrificed clinical precision in pursuit of an illusory sense of equity? 

It seems so. Proponents of a race-neutral equation claim that the race-corrected calculation underestimates renal disease severity in many black patients leading to delayed treatment. However, in his article, “Retaining Race in Chronic Kidney Disease Diagnosis and Treatment,” Paul Williams compares in great detail the race-corrected 2009 Chronic Kidney Disease Epidemiology Collaboration formula with the race-free 2021 version, showing that the 2009 formula better aligns with the true measure of GFR.[6]

Joel Velasco and Brad Snodgrass echoed this point in highlighting the harm to black patients by removing the race correction. They specifically noted the safe and effective prescribing and dosing of metformin necessitates an accurate eGFR.[7] Likewise, certain antibiotics, anticoagulants, and antihypertensives require a precise eGFR, not a political one. Even more critically, eGFR guides decisions on dialysis and transplant eligibility – making accuracy vital.

Delivering the highest quality care requires precision. While we have a moral obligation to treat people fairly, disregarding race when it can be clinically meaningful is misguided and can result in unequal treatment. May the same rigor being applied to thyroid diagnostics return to measures like eGFR, which were hastily politicized in the name of equity and at the expense of truth.

[1] Anderer S. Thyroid Disease May Be Overdiagnosed, Study Finds. JAMA. 2025;333(24):2134–2135. doi:10.1001/jama.2025.6466

[2] Qihang L, Yida T, Xuefeng Y, et al. Thyroid Function Reference Intervals by Age, Sex, and Race: A Cross-Sectional Study. Ann Intern Med. [Epub 6 May 2025]. doi:10.7326/ANNALS-24-01559

[3] Qihang L, Yida T, Xuefeng Y, et al. Thyroid Function Reference Intervals by Age, Sex, and Race: A Cross-Sectional Study. Ann Intern Med. [Epub 6 May 2025]. doi:10.7326/ANNALS-24-01559

[4] Qihang L, Yida T, Xuefeng Y, et al. Thyroid Function Reference Intervals by Age, Sex, and Race: A Cross-Sectional Study. Ann Intern Med. [Epub 6 May 2025]. doi:10.7326/ANNALS-24-01559

[5] Cerdeña JP, Plaisime MV, Tsai J. From race-based to race-conscious medicine: how anti-racist uprisings call us to act. The Lancet. 2020;396(10257):1125-1128

[6] Williams P. Retaining Race in Chronic Kidney Disease Diagnosis and Treatment. Cureus. 2023;15(9). doi: 10.7759/cureus.45054

[7] Velasco JD, Snodgrass B. The Use of Race in eGFR: Why Racial Justice Requires Accuracy. The American Journal of Medicine. 2021; 134(7):827-828