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Immunology & Autoimmune
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Currently under review
Pending specialist review and validation.
The intact parathyroid hormone test measures the active form of parathyroid hormone made by the parathyroid glands in your neck. This hormone helps keep calcium and phosphate in balance by acting on bone, kidneys, and vitamin D activation.
The test specifically detects the complete, bioactive hormone rather than fragments, which makes it useful for assessing true parathyroid gland activity. It is often ordered together with calcium, phosphate, magnesium, vitamin D, and kidney function tests to give a full picture of mineral and bone health.
Your parathyroid hormone level helps determine why calcium may be high or low and whether the parathyroid glands are overactive or underactive. Results can point to conditions such as primary parathyroid overactivity, a secondary response from low vitamin D or reduced kidney function, or suppression when calcium is elevated from other causes.
Clinicians use this test to diagnose and monitor parathyroid disorders, to assess bone strength risks, and to guide treatment such as vitamin D repletion, medication, or surgery. It is commonly checked when calcium is abnormal, during osteoporosis evaluations, before and after parathyroid surgery, and as part of chronic kidney disease care.
Your result is interpreted using your laboratory’s reference interval, your symptoms, and related tests. Calcium, albumin, phosphate, magnesium, vitamin D, and kidney function all affect how the number is understood, so results are rarely viewed in isolation.
A higher result may reflect parathyroid overactivity or a compensatory response to low calcium or vitamin D. A lower result may indicate suppression from high calcium or reduced hormone production. Your clinician may repeat testing, review medications and supplements, check vitamin D status, assess urine calcium, or arrange imaging when needed.
If you are being followed for kidney disease or after parathyroid surgery, patterns over time are more informative than a single value. Ask how your result fits into your overall plan for bone and mineral health.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
Parathyroid hormone has a daily rhythm and can shift with posture. Whenever possible, try to have repeat tests collected at a similar time of day and under similar conditions.
Low vitamin D or low calcium intake can drive the hormone higher, while high calcium intake can suppress it. Tell your clinician about supplements and diet patterns.
Reduced kidney function alters vitamin D activation and phosphate handling, which can raise the hormone as a secondary effect. Trends are especially important in kidney disease.
Lithium, thiazide or loop diuretics, calcimimetics like cinacalcet, bisphosphonates, denosumab, and some anticonvulsants can change levels or how they are interpreted. Share an up-to-date medication list.
High-dose biotin can interfere with some immunoassays and may falsely lower the result. Ask whether you should hold biotin supplements before your blood draw.
The hormone is sensitive to delays and warmth. Laboratories typically chill and process samples promptly. Collection and handling issues can artifactually lower the result.
Physiologic changes in pregnancy and differences across age groups can influence expected ranges. Your lab may apply population-specific reference intervals.
References