Is it appropriate to check hormone levels in asymptomatic patients?

Hormone Level Testing in Asymptomatic Patients

Routine hormone level testing is not recommended in asymptomatic adults due to insufficient evidence of clinical benefit and potential harms from overdiagnosis and overtreatment. 1

Thyroid Function Testing in Asymptomatic Adults

• The U.S. Preventive Services Task Force (USPSTF) found inadequate evidence that screening for thyroid dysfunction in nonpregnant, asymptomatic adults leads to clinically important benefits 1
• Screening for and treatment of thyroid dysfunction in asymptomatic adults does not improve quality of life or provide clinically meaningful improvements in blood pressure, BMI, bone mineral density, lipid levels, or cognitive function 1
• Potential harms of screening include frequent false-positive results, psychological effects of labeling, and overdiagnosis/overtreatment of biochemically defined abnormal TSH levels that may revert to normal without intervention 1
• About 37% of persons with subclinical hypothyroidism spontaneously revert to a euthyroid state without intervention after several years 1

Specific Considerations for Thyroid Testing

• TSH testing should be reserved for patients with symptoms suggestive of thyroid dysfunction or those in high-risk groups 2
• High-risk individuals who may warrant testing include:
  • Women of childbearing age before pregnancy or during first trimester 2
  • Women older than 50 years with symptoms that could be caused by thyroid disease 2
  • Elderly patients 2
  • Patients with type 1 diabetes 2
  • Patients on immune checkpoint inhibitor therapy 2

Hormone Testing in Other Conditions

• For obesity, with the exception of screening for hypothyroidism, most endocrine testing is not recommended in the absence of clinical features of endocrine syndromes 3
• In infertility evaluations, the practice of routinely ordering serum levels of TSH and prolactin in patients having normal menstrual periods has been questioned, with abnormal findings in only 2.48% (TSH) and 1.77% (prolactin) of asymptomatic patients 4
• For erectile dysfunction, detailed medical history and thorough physical examination can reduce the need for excessive hormone studies 5

Pitfalls to Avoid

• Overdiagnosis and overtreatment of subclinical thyroid dysfunction can lead to unnecessary lifelong treatment 6
• Laboratory reference intervals for TSH are based on statistical distribution rather than association with symptoms or adverse outcomes 1
• TSH levels may be misleading in severe non-thyroid illness (euthyroid sick syndrome) 2
• About 25% of patients on levothyroxine are unintentionally maintained on doses sufficient to fully suppress TSH, highlighting risks of treatment without clear indications 6

When Testing May Be Appropriate

• If clinicians offer screening for thyroid dysfunction to asymptomatic persons, they should first ensure that patients clearly understand the uncertainties surrounding potential clinical benefit and possible harms 1
• For patients with symptoms suggestive of hypothyroidism (fatigue, weight gain, cold intolerance) or hyperthyroidism (weight loss, palpitations, heat intolerance), TSH testing is indicated 2
• Consider TSH testing in patients with atrial fibrillation, especially in elderly patients 2

Recommendations for Testing When Indicated

• When testing is clinically indicated, TSH is the preferred initial test due to its high sensitivity (98%) and specificity (92%) 6
• Multiple tests over a 3-6 month interval may be needed to confirm or rule out abnormal findings 2
• Professional groups recommend repeating thyroid function tests if results fall outside reference intervals to confirm persistent dysfunction before making treatment decisions 1