What Is a Chloride Test?

Medically Reviewed by Jennifer Robinson, MD on May 02, 2023
4 min read

You may have heard of electrolytes and the role they play in keeping you hydrated and healthy.

One of the most important of these electrically charged minerals is chloride. It works with other electrolytes, such as sodium and potassium, to help balance acids and bases in your body.

It also helps move fluid in and out of your cells. So if your chloride levels drop, you can become sick and dehydrated. If your levels are too high, it often means your kidneys aren’t working properly.

There is a simple blood test to measure your chloride levels. The results can tell if your levels are good or if they are out of balance. This will help your doctor figure out where to look for the condition or medication that might be causing your imbalance.

You might hear this also called a “Cl test” or a “serum chloride test.”

It’s usually ordered with other blood tests when you are having your cholesterol, blood sugar, and other electrolytes such as sodium and potassium checked.

If your doctor is concerned about the health of your heart or kidneys, a chloride test can help explain what might be wrong.

Your chloride levels can drop if you have had bouts of vomiting or diarrhea. Diabetes can sometimes cause chloride levels to increase.

If you’re having symptoms such as weakness, constant tiredness, or dehydration, your doctor may order a chloride test.

You don’t need to do anything special before a blood test. If you’re scheduled for a urine chloride test, you should avoid alcohol for at least 24 hours before giving a sample.

The amount of fluids you drink before the test may affect the results, so ask your doctor whether you should change anything about your fluid intake. Vomiting or diarrhea in the days before the test may lead to a lower chloride result.

You should also tell your doctor all the prescription and over-the-counter medications you take, as well as any vitamins or supplements.

Some medications that may increase chloride levels include:

You may not need to change your medication routine. It’s just important that your doctor knows what you take, even if it’s aspirin for a headache.

You will usually have a blood sample taken at your doctor’s office or a lab. Chloride levels also can be checked with a urine test.

A lab tech will insert a needle into a vein in your arm to get the sample. Your arm may be a little sore where the blood was drawn. Some people become lightheaded for a few moments.

You should be able to get the results of your test within a few days. It may be sooner if your doctor has ordered that the results be checked at once.

The normal range for chloride in your blood is between 96 and 106 milliequivalents per liter (MEq/L). Some labs may vary in their definition of the normal range.

Talk with your doctor about your test results, especially if you’re outside the healthy range. Chloride levels tend to change if your sodium levels change, too.

Chloride levels above 106 could point to kidney problems, such as renal tubular acidosis (when your kidneys aren’t removing enough acids from your blood and into your urine).

Low levels have several other possible causes, including common, temporary problems such as vomiting and dehydration. Among the more serious causes are:

Testing the chloride levels in your blood or urine is practically painless and takes little time. The information it gives your doctor can help you avoid some painful and serious health problems down the road.