For immediate release
November 18, 2019
Screening for thyroid dysfunction in patients without symptoms: don’t routinely check that box
New guideline from the Canadian Task Force on Preventive Health Care
A new guideline from the Canadian Task Force on Preventive Health Care found no benefit of routine screening for thyroid dysfunction in adults without symptoms or risk factors. Based on the latest evidence, the Task Force guideline recommends against routine screening for thyroid dysfunction in non pregnant adults and is published in CMAJ (Canadian Medical Association Journal).
Routine screening for thyroid dysfunction in people without symptoms or risk factors is commonly ordered, but practice varies by primary care practitioner. When done, blood tests are ordered – by checking the box on a requisition – to measure Thyroid Stimulating Hormone (TSH) levels which may indicate an underactive (hypothyroidism) or overactive thyroid gland (hyperthyroidism).
“If you are a clinician who orders TSH tests as part of preventive health visits, we would like you to reconsider this practice. The evidence isn’t there to suggest a health benefit for this type of screening as a routine part of care,” says Dr. Richard Birtwhistle, Emeritus professor of Family Medicine and Public Health Sciences at Queen’s University and Chair of the Task Force Thyroid Dysfunction working group.
This recommendation does not apply to patients with symptoms, including unexplained fatigue or weight change, sensitivity to heat or cold, hair loss, and irregular heart rhythms. People on medications such as lithium or amiodarone or with risk factors for thyroid dysfunction, such as previous thyroid disease or surgery, radiation to head or neck or pituitary or hypothalamic diseases, are also exempt from this guideline.
Why did the Task Force make this recommendation?
The Task Force conducted a rigorous systematic review of the latest evidence. Although no screening trials were identified, 22 studies on the effectiveness of treatment for abnormal TSH findings in asymptomatic adults were included. The Task Force did not find evidence of benefits from screening and treatment in people without symptoms, but highlighted that screening requires patients to undergo testing.
Given the lack of benefit to patients, the need to take medication unnecessarily, and have regular medical visits and follow-up blood tests to check TSH levels, the Task Force strongly recommends against routine TSH screening in asymptomatic adults.
“Patients who are unusually tired, sensitive to cold or heat, experience hair loss, heartbeat irregularities, unexpected weight loss or gain should visit their primary care practitioner,” says Dr. Donna Reynolds, a family doctor and specialist in public health and preventive medicine and a member of the Task Force working group. “This recommendation does not apply to people with symptoms which may indicate an over active or under active thyroid gland, or who have risk factors for thyroid disease, such as previous head or neck radiation, exposure to certain medications and pituitary or hypothalamic diseases.”
Clinical practice implications
- This recommendation may change practice for clinicians who routinely screen for thyroid function in asymptomatic patients.
- Clinicians should be aware of symptoms, signs, and conditions associated with thyroid dysfunction so that patients with these can be tested, particularly symptomatic postmenopausal women, given the higher prevalence of hypothyroidism in that population.
Alignment with other guidelines
- The British Columbia Ministry of Health and Toward Optimized Practice from Alberta recommend against testing for TSH in asymptomatic patients.
The College of Family Physicians of Canada, Nurse Practitioner Association of Canada and the Canadian Society of Endocrinology and Metabolism have endorsed the guideline.
“Given the lack of clinical effectiveness and the burden on patients, including financial costs, screening patients without symptoms consumes resources that could be better used elsewhere,” says Dr. Birtwhistle.
For the full guideline, infographic overview and additional tools, click here. Listen to a related podcast on the guideline and read the systematic review published November 18 in the journal Systematic Reviews.
About the Canadian Task Force on Preventive Health Care
The Canadian Task Force on Preventive Health Care is an independent panel of health professionals who are experts in clinical preventive health care and guideline methodology. The Task Force’s mandate is to develop and disseminate evidence-based clinical practice guidelines for primary and preventive care.
“Recommendations on screening adults for asymptomatic thyroid dysfunction in primary care” is published November 18, 2019
Media contact for interviews: Kim Barnhardt, media@canadiantaskforce.ca or kim.barnhardt@cmaj.ca