Thyroid function studies are used to delineate the presence or absence of hormonal abnormalities of the thyroid and pituitary glands. These abnormalities may be either primary or secondary and often but not always accompany clinically defined signs and symptoms indicative of thyroid dysfunction.

Laboratory evaluation of thyroid function has become more scientifically defined. Tests can be done with increased specificity, thereby reducing the number of tests needed to diagnose and follow treatment of most thyroid disease. Measurements of serum sensitive thyroid-stimulating hormone (TSH) levels, complemented by determination of thyroid hormone levels [free thyroxine (fT-4) or total thyroxine (T4) with Triiodothyronine (T3) uptake] are used for diagnosis and follow-up of patients with thyroid disorders. Additional tests may be necessary to evaluate certain complex diagnostic problems or on hospitalized patients, where many circumstances can skew test results. When a test for total thyroxine (total T4 or T4 radioimmunoassay) or T3 uptake is performed, calculation of the free thyroxine index (FTI) is useful to correct for abnormal results for either total T4 or T3 uptake due to protein binding effects.

Indications

Thyroid function tests are used to define hyper function, euthyroidism, or hypofunction of thyroid disease. Thyroid testing may be reasonable and necessary to:

• distinguish between primary and secondary hypothyroidism;
• confirm or rule out primary hypothyroidism;
• monitor thyroid hormone levels (for example, patients with goiter, thyroid nodules, or thyroid cancer);
• monitor drug therapy in patients with primary hypothyroidism;
• confirm or rule out primary hyperthyroidism, and; monitor therapy in patients with hyperthyroidism.

Thyroid function testing may be medically necessary in patients with disease or neoplasm of the thyroid and other endocrine glands. Thyroid function testing may also be medically necessary in patients with metabolic disorders; malnutrition; hyperlipidemia; certain types of anemia; psychosis and non-psychotic personality disorders; unexplained depression; ophthalmologic disorders; various cardiac arrhythmias; disorders of menstruation; skin conditions; myalgias; and a wide array of signs and symptoms, including alterations in consciousness; malaise; hypothermia; symptoms of the nervous and musculoskeletal system; skin and integumentary system; nutrition and metabolism; cardiovascular; and gastrointestinal system.

It may be medically necessary to do follow-up thyroid testing in patients with a personal history of malignant neoplasm of the endocrine system and in patients on long-term thyroid drug therapy.

Limitations

Testing may be covered up to two times a year in clinically stable patients; more frequent testing may be reasonable and necessary for patients whose thyroid therapy has been altered or in whom symptoms or signs of hyperthyroidism or hypothyroidism are noted.

With the exception of routine or screening, any diagnosis other than those listed under the “Covered Diagnosis Codes” section will be denied as not medically necessary. A provider cannot bill the member for the denied service unless the provider has given advance written notice, informing the member that the service may be deemed not medically necessary and providing an estimate of the cost. The member must agree in writing to assume financial responsibility, in advance of receiving the service. The signed agreement, in the form of a Pre-Service Denial Notice, should be maintained in the provider's records.

Thyroid testing for routine or screening purposes is excluded from coverage.  Therefore, any diagnosis code listed under the “Screening Diagnosis Codes” section will deny as not covered. The provider can bill the member for the non-covered service.

NOTE:

A claim for a test for which there is a national coverage or local medical review policy will be denied as not reasonable and necessary if it is submitted without a diagnosis code or narrative diagnosis listed as covered in the policy unless other medical documentation justifying the necessity is submitted with the claim. Also, if a national or local policy identifies a frequency expectation, a claim for a test that exceeds that expectation may be denied as not reasonable and necessary, unless it is submitted with documentation justifying increased frequency.

Failure to provide documentation of the medical necessity of tests may result in denial of claims. Such documentation may include notes documenting relevant signs, symptoms or abnormal findings that substantiate the medical necessity for ordering the tests. In addition, failure to provide independent verification that the test was ordered by the treating physician (or qualified nonphysician practitioner) through documentation in the physician’s office may result in denial.

NOTE:

This policy is designed to address medical guidelines that are appropriate for the majority of individuals with a particular disease, illness, or condition. Each person's unique clinical circumstances may warrant individual consideration, based on review of applicable medical records.

Title XVIII of the Social Security Act, Section 1862(a)(7). This section excludes routine physical examinations.

Title XVIII of the Social Security Act, Section 1862(a)(1)(A) states that no payment shall be made for items or services which are not reasonable and necessary for the diagnosis or treatment of illness or injury.

Title XVIII of the Social Security Act, Section 1833(e) states that no payment shall be made to any provider for any claim that lacks the necessary information to process the claim

National Coverage Determination - 190.22

On-Line NCD Coding Policy Manual and Change Report

Transmittal 534, CR 3806

Transmittal 651, CR 4005

Transmittal 758, CR 4161

Transmittal 864, CR 4328

Transmittal 1050, CR 5293

Transmittal 1093, CR 5384

Transmittal 1531, CR 6084

Transmittal 1606, CR 6213

Transmittal 1645, CR 6304

Transmittal 1766, CR 6548

Transmittal 1963, CR 6964

Transmittal 2080, CR 7204

Covered Diagnosis Codes

Non-covered Diagnosis Codes

Screening Diagnosis Codes