Parathyroid hormone-related protein blood test
Definition
The parathyroid hormone-related protein (PTH-rP) test measures the level of a hormone in the blood, called parathyroid hormone-related protein.
How the Test is Performed
How to Prepare for the Test
No special preparation is necessary.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing or slight bruising. This soon goes away.
Why the Test is Performed
This test is done to find out whether a high blood calcium level is caused by an increase in PTH-related protein.
Normal Results
No detectable (or minimal) PTH-like protein is normal.
Women who are breastfeeding may have detectable PTH-related protein values.
Normal value ranges may vary slightly among different labs. Some labs use different measurements or may test different specimens. Talk to your health care provider about the meaning of your specific test results.
What Abnormal Results Mean
An increased level of PTH-related protein with a high blood calcium level is usually caused by cancer.
PTH-related protein can be produced by many different kinds of cancers, including those of the lung, breast, head, neck, bladder, and ovaries. In about two thirds of people with cancer who have a high calcium level, a high level of PTH-related protein is the cause. This condition is called humoral hypercalcemia of malignancy (HHM) or paraneoplastic hypercalcemia.
Risks
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another, and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Multiple punctures to locate veins
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
References
Bilezikian JP, Walker MD, Binkley N, Goltzman D, Mannstadt M. Hormones and disorders of mineral metabolism. In: Melmed S, Auchus, RJ, Goldfine AB, Rosen CJ, Kopp PA, eds. Williams Textbook of Endocrinology. 15th ed. Philadelphia, PA: Elsevier; 2025:chap 27.
Klemm KM, Klein MJ, Zhang Y. Biochemical markers of bone metabolism. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 16.
Thakker RV. The parathyroid glands, hypercalcemia and hypocalcemia. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 227.
Review Date: 4/24/2025
Reviewed By: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language.
© 1997-
A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
All content on this site including text, images, graphics, audio, video, data, metadata, and compilations is protected by copyright and other intellectual property laws. You may view the content for personal, noncommercial use. Any other use requires prior written consent from Ebix. You may not copy, reproduce, distribute, transmit, display, publish, reverse-engineer, adapt, modify, store beyond ordinary browser caching, index, mine, scrape, or create derivative works from this content. You may not use automated tools to access or extract content, including to create embeddings, vectors, datasets, or indexes for retrieval systems. Use of any content for training, fine-tuning, calibrating, testing, evaluating, or improving AI systems of any kind is prohibited without express written consent. This includes large language models, machine learning models, neural networks, generative systems, retrieval-augmented systems, and any software that ingests content to produce outputs. Any unauthorized use of the content including AI-related use is a violation of our rights and may result in legal action, damages, and statutory penalties to the fullest extent permitted by law. Ebix reserves the right to enforce its rights through legal, technological, and contractual measures.
All rights reserved