How To Use CPT Code 84439

CPT 84439 is a code used for measuring free thyroxine (T4) levels in a patient’s blood, which can help diagnose thyroid-related conditions. This article will cover the description, procedure, qualifying circumstances, usage, documentation requirements, billing guidelines, historical information, similar codes, and examples of CPT 84439.

1. What is CPT 84439?

CPT 84439 is a code used in the medical billing and coding field to represent a laboratory test that measures the levels of free thyroxine (T4) in a patient’s blood. Free T4 is the active form of thyroxine that is unbound to proteins in the blood and is produced by the thyroid gland. This test is typically ordered by clinicians to evaluate patients with abnormal thyroid-stimulating hormone (TSH) levels and can help diagnose conditions such as Graves’ disease, Hashimoto’s disease, and other types of hyperthyroidism or hypothyroidism.

2. 84439 CPT code description

The official description of CPT code 84439 is: “Thyroxine; free.”

3. Procedure

1. A lab analyst collects a patient’s blood sample, typically through venipuncture.
2. The blood sample is processed to obtain the serum.
3. The serum is mixed with specific substances to measure the levels of free thyroxine (T4).
4. Methods such as immunoassay are used to determine the amount of free T4 in the specimen, where patient antibodies react with reagent antigens.
5. The results are analyzed and reported to the ordering clinician for further evaluation and diagnosis.

4. Qualifying circumstances

Patients who are eligible to receive CPT code 84439 services are those with abnormal thyroid-stimulating hormone (TSH) levels or suspected thyroid-related conditions. Clinicians may order this test to further evaluate patients presenting symptoms of hyperthyroidism or hypothyroidism, such as weight changes, fatigue, hair loss, or changes in heart rate. Additionally, patients with a family history of thyroid disorders or those taking medications that can affect thyroid function may also be eligible for this test.

5. When to use CPT code 84439

It is appropriate to bill the 84439 CPT code when a clinician orders a free thyroxine (T4) test to evaluate a patient’s thyroid function and diagnose potential thyroid-related conditions. This test is typically ordered when a patient presents with abnormal TSH levels or symptoms indicative of hyperthyroidism or hypothyroidism. The results of the test can help the clinician determine the appropriate course of treatment for the patient’s condition.

6. Documentation requirements

To support a claim for CPT 84439, the following information should be documented:

• Patient’s demographic information, including name, date of birth, and insurance information.
• Ordering clinician’s information, including name, contact details, and National Provider Identifier (NPI) number.
• Indication for the test, such as abnormal TSH levels or symptoms of thyroid dysfunction.
• Date and time of the blood sample collection.
• Method used for the test, such as immunoassay.
• Results of the free T4 test, including reference ranges for comparison.
• Any additional relevant clinical information or patient history.

7. Billing guidelines

When billing for CPT code 84439, it is essential to follow the specific guidelines and rules set by the payer. Some payers may pay separately for the collection of the blood sample using a code such as 36415, Collection of venous blood by venipuncture. Additionally, use code 84436, Thyroxine, total, for total thyroxine, which includes both the bound and unbound, or free, T4. Ensure that all required documentation is complete and accurate to support the claim and avoid potential denials or delays in payment.

8. Historical information

CPT 84439 was added to the Current Procedural Terminology system on January 1, 1990. There have been no significant updates to the code since its addition.

9. Similar codes to CPT 84439

Five similar codes to CPT 84439 and how they differentiate are:

• CPT 84436: This code is used for measuring total thyroxine (T4) levels, which includes both bound and unbound T4.
• CPT 84443: This code represents a test for thyroid-stimulating hormone (TSH), which is often ordered alongside the free T4 test.
• CPT 84479: This code is used for measuring unbound (free) triiodothyronine (T3), another hormone produced by the thyroid gland.
• CPT 84480: This code is for measuring total triiodothyronine (T3) levels, which includes both bound and unbound T3.
• CPT 84481: This code represents a test for reverse triiodothyronine (rT3), an inactive form of T3 that can provide additional information about thyroid function.

10. Examples

Here are 10 detailed examples of CPT code 84439 procedures:

1. A patient with a family history of Graves’ disease presents with symptoms of weight loss, increased heart rate, and tremors. The clinician orders a free T4 test to evaluate the patient’s thyroid function.
2. A patient with a history of hypothyroidism is experiencing fatigue, weight gain, and hair loss. The clinician orders a free T4 test to assess the effectiveness of the patient’s current thyroid medication.
3. A patient presents with an abnormal TSH level during a routine physical examination. The clinician orders a free T4 test to further evaluate the patient’s thyroid function.
4. A patient with a history of thyroid cancer undergoes a free T4 test as part of their post-treatment monitoring plan.
5. A patient taking lithium for bipolar disorder undergoes a free T4 test to monitor potential effects on their thyroid function.
6. A pregnant patient with a history of hypothyroidism undergoes a free T4 test to ensure proper thyroid function during pregnancy.
7. A patient with a goiter presents with difficulty swallowing and breathing. The clinician orders a free T4 test to evaluate the patient’s thyroid function.
8. A patient with a history of Hashimoto’s disease experiences a sudden onset of symptoms indicative of hyperthyroidism. The clinician orders a free T4 test to assess the patient’s thyroid function.
9. A patient with a family history of thyroid disorders undergoes a free T4 test as part of a preventive screening plan.
10. A patient with a history of thyroidectomy due to Graves’ disease undergoes a free T4 test to monitor their thyroid hormone replacement therapy.