Hypercalcemia is the medical word for “high blood calcium.” It is almost never normal and almost always requires further testing and often treatment of the underlying problem to bring the high blood calcium back into the normal range. Hypercalcemia should not be ignored or just “monitored” because it typically means bad things are on the way. Calcium is one of the most important minerals in your body that serves many functions and thus it needs to be kept in a very tight range – you don’t want too little OR too much of it. Because a normal blood calcium is required for good health, the measurement of blood calcium levels is part of the standard blood tests when patients have an annual checkup, or go to the doctor (or emergency room) when feeling ill. When your doctor orders routine blood tests, calcium is usually part of the standard panel (it’s in the Basic Metabolic Panel, one of the most common blood tests).

What Physicians Need to Know About Hypercalcemia

Many physicians end up on this page after searching "hypercalcemia" online. The most important thing for doctors to know is that hypercalcemia is almost never caused by cancer in the ambulatory patient. If you have a patient in your office that isn't dying of cancer (that you have already known about for months or years), then the hypercalcemia is almost always due (over 99%) to primary hyperparathyroidism. Cancers do not present with high calcium--in fact, very few cancers are ever associated with high blood calcium, and when they are, the patient is already in the hospital (in the ICU?) and end-of-life preparations have been ongoing for months. An ambulatory patient with hypercalcemia does NOT need any form of cancer work up. They do not need a CT scan, MRI scan, PET scan or even a chest-x-ray to "rule out" cancer. Virtually every patient in every doctors office (even an oncologist's office) with hypercalcemia should be presumed to have hyperparathyroidism and tests run to confirm this diagnosis outlined on our Parathyroid Advanced Diagnosis page. There is a lot of very valuable information for doctors and patients further down on this current page, so keep reading.
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Hypercalcemia Quick Tip

The definition of hypercalcemia is different for different age groups. Teenagers who are building bone are supposed to have blood calcium levels a little bit higher than adults over 30 years old who are not building bone. Thus hypercalcemia in teenagers means calcium levels above 10.6 mg/dl (2.65 mmol/l) but in adults hypercalcemia means any calcium levels above 10.1 mg/dl (2.52 mmol/l). Be careful because many laboratories do not give the normal range according to the age of the patient, instead they just give the highest normal range for teenagers to everybody. Many doctors are not aware this happens. Check out our cool Hypercalcemia Calculator below.

Hypercalcemia vs. Normal Calcium Levels Will Change According to your Age

Most labs will give a normal calcium range from about 8.8 to 10.5 mg/dl. But this doesn’t mean that this is a normal range for everyone – it depends on your age (we have a calculator for you further down on this page). A value of 10.5 in a teenager is perfectly normal, but 10.5 in adult over age 35 is too high – this is hypercalcemia. The graph below shows the normal range of blood calcium in green and you can see that it changes as we get older. Teenagers and young adults can have normal calcium levels up into the mid 10s (mg/dl). But adults over the age of about 35 should have lower calcium levels, not going above 10.0 mg/dl. (NOTE: Canadian and European version of this graph is at the bottom of this page). Adult calcium levels usually range somewhere between 9.0 and 10.0 mg/dl, which is why we like to say that “adults live in the 9s”. It is typically not normal for adults to have frequent or persistent calcium levels in the 10s.

Hypercalcemia changes as we age. The green area shows the normal range for blood calcium according to our age.

Hypercalcemia Calculator: Calculate the Upper Limit of Blood Calcium for your Age

Enter your age and our calculator will give the upper limit of normal calcium for you.

The Upper Limit of Calcium for your age is [Enter Your Age Above] mg/dl in the USA, and [Enter Your Age Above] mmol/L in most other countries. Calcium levels above this should be considered too high for your age.

The upper limit of calcium varies with age with teenagers having the highest levels and adults over 50 having the lowest. Unfortunately, most labs don't give the upper limit of normal according to your age, so we have made this calculator for you. Note that blood calcium is measured differently in different parts of the world. Just as we measure distance in feet and miles in the USA, while other countries use meters and kilometers; in the USA we measure calcium with the units mg/dl while most other countries use the units mmol/L. The units your lab uses will be printed right next to your results.

Hypercalcemia is almost always caused by Hyperparathyroidism

Hypercalcemia can be caused by only a few things. Often people are told that hypercalcemia is caused by cancer, but this is extremely rare. We have an entire page on the different causes of hypercalcemia (including different types of cancer) that you can read (click here), but it is important to understand that over 99% of cases of hypercalcemia are caused by a parathyroid gland tumor; a disease called hyperparathyroidism.

People with parathyroid disease (hyperparathyroidism) almost always have hypercalcemia: they have blood calcium levels in the 10s or higher. The graph below shows highest calcium levels for over 20,000 consecutive adults with parathyroid disease who were treated at our center. About half of patients with hyperparathyroidism (a parathyroid tumor causing hypercalcemia) have calcium levels between 10.0 and 11.0 mg/dl, and half have calcium levels above 11.0 mg/dl.

Hypercalcemia: Highest Blood Calcium Levels in 20,000 Patients Undergoing Parathyroid Surgery at the Norman Parathyroid Center

What’s wrong with hypercalcemia? Don’t I need lots of calcium for my bones?

Hypercalcemia is not good, and actually, can be quite bad for you. It is now known that even mild elevations in blood calcium (mild hypercalcemia) can be very detrimental to your overall health over time. The high blood calcium can cause many problems with many different parts of the body, but it also makes people feel bad.

Hypercalcemia will cause symptoms in almost everyone. The most common symptoms of hypercalcemia are chronic fatigue, lack of energy, loss of interest in things you used to enjoy, "brain fog" or difficulty concentrating, and trouble with sleep. It also causes kidney stones, heartburn or gastric reflux (GERD), headaches, depression, high blood pressure, palpitations or cardiac arrhythmias, and chronic kidney failure. And because calcium is coming out of your bones, it causes a loss in bone density, leading to osteopenia and osteoporosis. Hypercalcemia can make you miserable. The most popular page of this large website is the Symptoms of Hyperparathyroidism page.

Here is the most important thing to know about the symptoms of hypercalcemia: they are NOT correlated with how high the calcium is. That is, someone with only a slightly high calcium can feel just as bad as someone with a much higher blood calcium level, and they will have the same chances of getting all of the complications. Some doctors out there do not know this! In medical school they were taught that the calcium level determined how bad the disease was, so a mild hypercalcemia meant a mild disease and worse hypercalcemia meant worse problems. In treating tens of thousands of patients with hyperparathyroidism, we know this is not true. Mild hypercalcemia is just as bad as more pronounced hypercalcemia. This is illustrated very nicely in the graph below where we looked at over 20,000 patients operated on for hyperparathyroidism and hypercalcemia. It shows that people with only mild elevations of blood calcium (between 10 and 11 mg/dl) have just as many symptoms and complications from the high calcium as people with much higher calcium levels (above 11.1 mg/dl).

Hypercalcemia: Frequency of common symptoms and complications of  Hyperparathyroidism
Hypercalcemia complications develop over time. Thus the severity of hypercalcemia is related to how long you have calcium levels that are high, not how high it has become. A calcium of 10.5 is just as dangerous as a calcium of 11.5. Even "mild" hypercalcemia will lead to many other health problems if left untreated. It is the duration of hypercalcemia that matters, not the height of the calcium!

Hypercalcemia Causes: An Overview

Hypercalcemia is almost always caused by a parathyroid tumor (called primary hyperparathyroidism). Parathyroid glands are tiny endocrine glands in your neck, next to your thyroid. You have four of them, and the only thing they do is control blood calcium levels. They do this by making parathyroid hormone (PTH), which raises the blood calcium level by taking calcium out of your bones. A normal parathyroid gland will produce just enough PTH to keep your blood calcium level in normal range. A parathyroid tumor will produce more PTH than necessary, which will push the calcium level up. Parathyroid tumors are benign in almost every case, so you don’t need to worry about cancer.

If you have been told that you have hypercalcemia, the overwhelming odds are that you have a parathyroid tumor. There are a few other causes of hypercalcemia, which you can read about on our page on Causes of High Blood Calcium, but they are much, much less common. Hypercalcemia is almost always due to a parathyroid problem.

Hypercalcemia Diagnosis

Hypercalcemia is diagnosed by a blood calcium test. If the calcium is high, then you have hypercalcemia. The next step is to figure out what the cause of hypercalemia is. Since almost all hypercalcemia is caused by a parathyroid problem, the obvious next step is to measure the amount of parathyroid hormone (PTH) in the blood. This is a simple blood test. If you have hypercalcemia and a PTH level that is in the high or normal range, then you have a parathyroid tumor. Note that a high PTH level isn’t required to make the diagnosis of hyperparathyroidism as the cause of the hypercalcemia—but the PTH level can’t be low. Scans, x-rays, and imaging tests are NOT to be used to diagnose hyperparathyroidism -- it is diagnosed on blood tests alone. We have two very excellent pages on the diagnosis of hyperparathyroidism: 1) The Diagnosis of Hyperparathyroidism, and 2) Advanced Diagnosis Tricks for Hyperparathyroidism.

Hypercalcemia Treatment

Since hypercalcemia is almost always due to a parathyroid tumor, and there are no medications that can treat this – the treatment is to remove the tumor. Fortunately, parathyroid surgery is curative and can be done in a minimally invasive outpatient operation. Removing the parathyroid tumor is the only way to cure almost every case of hypercalcemia.

Everyone with primary hyperparathyroidism is a candidate for this operation. As mentioned above, even “mild” hypercalcemia will lead to problems if left untreated. There is no reason to wait for these complications to occur. Get the tumor out of your neck before it does damage! Read some of our patient testimonials to learn about how this simple operation can be life-changing.

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