Current Procedural Terminology (CPT) codes are standardized, five-digit codes used for reporting medical services and procedures to payers, such as insurance companies. CPT Code 82306 specifically identifies a laboratory procedure for quantifying vitamin D in a patient’s blood. This test is a common diagnostic tool used by physicians to assess vitamin D status. The following sections explore the marker measured, the procedure itself, and how the results are interpreted.
Defining the Vitamin D Marker
CPT 82306 measures the total concentration of 25-hydroxyvitamin D, also known as calcidiol, circulating in the blood. Vitamin D obtained through sun exposure or diet is converted in the liver to this form. Since this is the body’s primary storage form, its blood level is the most reliable indicator of total vitamin D reserves.
The test quantifies both 25-hydroxyvitamin D2 (ergocalciferol) and 25-hydroxyvitamin D3 (cholecalciferol) for a comprehensive total. D2 comes from plant sources and supplements, while D3 is produced in the skin via sun exposure and found in fortified foods. Measuring this precursor is preferred over the active hormone, 1,25-dihydroxyvitamin D (calcitriol), which is tightly regulated by the kidneys and remains stable even when stores are low.
Physicians order this test for individuals with risk factors or conditions associated with low vitamin D levels. Indications include chronic kidney disease, hyperparathyroidism, and conditions causing poor nutrient absorption, such as celiac disease or bariatric surgery. The test helps diagnose and manage bone disorders, including osteomalacia and osteoporosis. It is also used for monitoring the effectiveness of vitamin D replacement therapy after a deficiency has been identified.
The Testing Procedure
The CPT 82306 procedure begins with a standard blood collection, known as venipuncture, typically performed by a phlebotomist. Preparation usually involves no specific requirements, and fasting is not generally necessary. The timing of the blood draw can be important for monitoring purposes, such as drawing the sample before a scheduled dose of a high-potency supplement.
A small volume of blood is drawn and collected into a tube to separate into a serum sample. The serum, containing the 25-hydroxyvitamin D, is transported to a laboratory for analysis. The sample is processed using a chemical assay to accurately quantify the vitamin D marker concentration.
Many modern laboratories use highly accurate methods, such as liquid chromatography with tandem mass spectrometry (LC-MS/MS), for this quantification. This technology precisely separates and measures the D2 and D3 components, ensuring an accurate total reading. The result generated is a single numerical value representing the total level of 25-hydroxyvitamin D in nanograms per milliliter (ng/mL) or nanomoles per liter (nmol/L). This result is then reported back to the ordering physician for interpretation.
What Your Results Mean
The numerical result from the CPT 82306 test categorizes a patient’s vitamin D status into clinical ranges. While specific reference values vary slightly between laboratories, accepted ranges provide a framework for interpretation. Levels of 30 ng/mL (or 75 nmol/L) and above are considered sufficient for bone and overall health.
A result between 20 ng/mL and 30 ng/mL (50–75 nmol/L) is classified as vitamin D insufficiency. This suggests the level is not optimal for supporting the body’s calcium absorption. Readings below 20 ng/mL (50 nmol/L) are categorized as vitamin D deficiency, a level that negatively affects bone mineralization and can lead to serious health issues.
Based on these results, a physician determines the appropriate course of action, often recommending supplementation. For patients with deficient or insufficient levels, intervention usually includes prescribing specific dosages of vitamin D supplements to raise blood concentration. Dietary adjustments and recommendations for safe sun exposure might also be discussed to help maintain adequate levels.
Follow-up testing is common to ensure the treatment plan is effective and that vitamin D levels reach the target range. Repeat testing is scheduled three to four months after starting replacement therapy, allowing time for stored levels to stabilize. Once a sufficient level is maintained, testing frequency is typically reduced, often limited to an annual check.