Understanding Thyroid Disease

Thyroid disease impacts an estimated 20 million people in the United States, and many are unaware they are affected. The thyroid is a butterfly-shaped organ in the front of the neck which secretes hormones and regulates calcium. Thyroid disease may manifest as hyperthyroidism (too much activity) or hypothyroidism (too little activity). If left untreated it can cause severe symptoms including death. Thyroid disease and testing has been previously described in this article series.

Given thyroid disease is such a common condition, physicians often order a variety of tests for the evaluation of hyperthyroidism, hypothyroidism, or other associated conditions. Indeed, the Department of Health and Human Services (HHS) Office of Inspector General (OIG) reported that Medicare Part B spent $336 million on thyroid stimulating hormone testing in 2020, which puts it in the top five tests for Medicare Part B reimbursement. Furthermore, Medicare Part B spent over $92 million on parathyroid hormone testing in 2020, which makes it the 15th most expensive test collectively reimbursed in 2020. With combined testing costing almost half a billion dollars in 2020, it is important to reduce overutilization and unnecessary testing for the evaluation of thyroid disease.

Thyroid Testing Cascade

Typically, a thyroid testing cascade is utilized, which will automatically reflex to other tests, depending on results of the previous test. The cascade begins with a third-generation thyroid-stimulating hormone (TSH) test. If the TSH result is normal, a euthyroid status is assumed and testing stops. The cascade may include a combination of thyroid stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), and thyroid peroxidase antibodies (TPO), depending on the clinical scenario. However, data suggests there is quite a bit of variability among providers regarding thyroid testing, and some may not follow ordering guidelines.  Unnecessary lab testing in general, is a waste of precious time, resources, and can lead to patient harm.  Regardless of the cause, there are solutions available to increase efficiency by practicing laboratory stewardship when the clinician is deciding what testing strategy is appropriate for thyroid conditions.

The literature has documented successful reduction in clinician ordering patterns when specific quality initiatives are implemented. Provider education in the form of in-person seminars to clinical team leaders can raise awareness of appropriate testing, inappropriate testing, and medical guidelines for evaluating a patient for thyroid disease. One Canadian study reported a 13% relative reduction of thyroid testing when provider education was implemented. While provider education has proven to be successful, it requires a considerable amount of labor and work hours by those involved (both teaching and learning).

In contrast, clinical decision support systems may be integrated into the electronic health record (EHR) and electronic ordering system. Clinical decision support is a form of Artificial Intelligence (AI) that uses medical data, patient information, and evidence-based guidelines that can flag inappropriate testing and suggest better options. For example, if a clinician orders T4 and T3, the decision support can suggest that the clinician order the thyroid cascade instead.  It may also introduce “hard stops” where it is impossible to electronically order inappropriate testing in certain clinical scenarios. For example, if a different provider ordered a thyroid cascade the day previously, the current provider could be alerted and the repeat cascade order stopped. Moreover, it may serve as a resource to clinicians to provide easy access to the most recent guidelines and guidance documents about the disease and appropriate lab testing. Currently, there is a tremendous amount of research regarding clinical decision support systems for cascade thyroid testing in addition to thyroid imaging.

Medical centers must work with their IT support to upgrade and/or install the clinical decision support system within an existing EHR. Although the initial work of installing and upgrading is significant, clinical decision support systems can be scaled when installed in large health systems, and the potential impact may be exponential.  One hospital was able to reduce thyroid testing by 39.1% by utilizing a clinical support decision system with hard stops.  Another study reported a 43% reduction in thyroid testing overutilization when clinical decision support systems were combined with traditional physician education. Given the current technological capabilities of AI and the EHR, clinical decision support systems will likely be essential to reducing thyroid testing overutilization.

There are many medical professional societies that have evidence-based guidelines for thyroid testing, including the American Thyroid Association, the American Association of Clinical Endocrinologists, the American College of Physicians, the Endocrine Society, and the American Medical Association. However, the complexity of thyroid disease management and practicing medicine during a multi-year global pandemic may cause clinicians to be overburdened. Quality improvement initiatives such as clinician education and clinical support decision systems have reduced unnecessary testing in many different settings. If hospital systems in the United States applied these quality initiatives, the combined impact would be substantial. As the current COVID-19 pandemic continues and lab resources are stretched thin, implementing provider education and clinical decision support systems are critical to practice laboratory stewardship.


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American Association of Clinical Chemistry (AACC): How do you use quality improvement methods to reduce unnecessary free thyroid hormone testing? https://www.aacc.org/science-and-research/scientific-shorts/2021/how-do-you-use-quality-improvement-methods-to-reduce-unnecessary-free-thyroid-hormone-testing. Accessed 06/25/2022.

American Association of Clinical Endocrinology: https://www.aace.com/disease-and-conditions/thyroid/all-about-thyroid. Accessed 06/25/2022.

American Thyroid Association: https://www.thyroid.org/media-main/press-room/#:~:text=An%20estimated%2020%20million%20Americans,thyroid%20disorder%20during%20her%20lifetime. Accessed 06/25/2022.

Data Brief: COVID-19 Tests Drove an Increase in Total Medicare Part B Spending on Lab Tests in 2020, While Use of Non-COVID-19 Tests Decreased Significantly, OEI-09-21-00240. Available at: https://oig.hhs.gov/oei/reports/OEI-09-21-00240.asp. Accessed 06/25/2022.

Mayo Clinic Laboratories: Thyroid Function Ordering Algorithm. https://www.mayocliniclabs.com/~/media/it-mmfiles/special-instructions/Thyroid_Function_Ordering_Algorithm.pdf. Accessed 06/25/2022.