Calcium is important for the body, but too much of it is never considered “normal.” Having high blood calcium is because of parathyroid disease almost 100% of the time and the PTHrP blood test can help to determine if it is present. The parathyroid glands are at the back of the neck and they control how much calcium goes into the blood stream. When calcium levels are high, then there is a strong chance that there is a small tumor on one of those glands.
Although there are some tumors that do turn malignant during the development of parathyroid disease, the risks are less than 1%. High calcium levels can be an indicator of lung, breast, or kidney cancer, as well as a cancer in the head or neck. Multiple myeloma may also cause high calcium levels. The PTHrP blood test results will help to screen for problematic health conditions so that a doctor can properly diagnose the problem.
The PTHrP Blood Test Is Not Used For Screening
Just because you have a positive PTHrP blood test does not automatically mean that you have cancer. About 80% of people who have a malignant tumor and high levels of calcium and from that group, about half will have a positive blood test result. This means levels will usually be less than 30 pg/mL, but it may also be undetectable.
For test results that are above 30 gp/mL, the most common cause of the high calcium levels is actually hyperparathyroidism, which is a very treatable condition. This typically happens in the 65+ population and will be considered a diagnosis if there isn’t a family or personal history of cancer.
The bottom line is this: less than 0.5% of people will test positive for cancer after having an abnormal PTHrP blood test. It is more likely that there is a more common issue going on that is causing calcium levels to be too high.
What If Calcium Levels Are Too Low?
If the PTHrP blood tests come back and show that calcium levels are too low, then this is generally an indication that someone isn’t getting enough Vitamin D. This may be because of lifestyle habits. Your doctor may order nutritional changes to increase the levels of this vitamin or order a supplement to be taken. Low calcium levels can also be an indication that cancer may be present, however, so additional screenings may also be ordered.
Why Would Calcium Levels Be Too High?
There are some life events that can actually cause the PTHrP blood test results to be abnormal, even though the condition will be temporary. Women who are newly pregnant almost always have higher than normal parathyroid hormone-related peptides in their blood. New mothers who are lactating also tend to have higher than normal levels that could cause an abnormal test result. Newborns also tend to test positive with this blood test.
For those who have been diagnosed with HIV, there are certain co-existing conditions that may also cause higher than normal levels of calcium. Lymphedema, benign tumors of the endocrine system, kidney health issues, and benign tumors in the reproductive system may cause high levels of calcium.
Children and young adults may also test temporarily high when given the PTHrP blood test. This is because tooth eruption tends to spike the results.
A rare issue that sometimes happens is that the presence of heterophile antibodies can cause a false positive result. This may happen after a viral infection or disease, such as rheumatic fever. Anything that attacks heart tissues will create these antibodies, as well as the presence of lupus. When this result occurs, it is important to speak with your doctor about additional screenings as there may be a serious disease present.
How Long Does It Take To Get Results?
You can have this blood test taken on the same day it is ordered if you wish. Many laboratories will only perform this test 2x-3x per week because the specimen retention time [your blood draw] will be valid for up to 3 months. Once the test is initiated, it generally takes about 48 hours to receive results. For most people, this means having their PTHrP blood test results explained to them will generally take 5 days or less for a complete answer.
If there is high blood calcium present, your doctor will want to screen further for the presence of cancer to rule it out. Sometimes the cause of a high PTHrP blood test is not known. It is important to remember, however, that high blood calcium levels are never considered normal. There are no medical exceptions to this.