What is a chloride blood test?
Chloride is an electrolyte that helps keep a proper fluid and acid-base balance in your body. The chloride blood test, or serum chloride level, is often a part of a comprehensive metabolic panel or a basic metabolic panel.
A metabolic panel also measures your levels of other electrolytes, including carbon dioxide, potassium, and sodium. The proper balance of these electrolytes is critical for the normal functioning of the muscles, heart, and nerves. It’s also essential for normal fluid absorption and excretion.
This test detects abnormal blood chloride levels for your doctor to diagnose certain health conditions. These conditions include alkalosis, which happens when your blood is either too alkaline or basic, and acidosis, which happens when your blood is too acidic. The blood test can also be used to monitor conditions such as:
- high blood pressure
- heart failure
- kidney disease
- liver disease
These conditions can cause an electrolyte imbalance. The symptoms that may indicate a chloride imbalance include:
- excessive fatigue
- muscle weakness
- breathing problems
- frequent vomiting
- prolonged diarrhea
- excessive thirst
- high blood pressure
For accurate results, you shouldn’t drink or eat anything during the eight hours leading up to the test. Hormones, nonsteroidal anti-inflammatory drugs (NSAIDs), and diuretics can affect your test results. You should avoid taking them if you can.
Tell your doctor about any medications you take and whether they’re over-the-counter (OTC) or prescription drugs. You may need to stop taking these medications before the test.
Drawing blood is a routine laboratory test. There are very few risks involved. Rare side effects include:
- excessive bleeding
- dizziness or fainting
- blood accumulation beneath your skin, which is called a hematoma
- infection at the puncture site
Infections rarely occur if the person performing the blood draw follows proper procedure. Call your doctor right away if the puncture doesn’t close on its own or if you start to have pain and swelling in the area.
During the test, blood will be drawn from a vein on the inside of your elbow or the back of your hand. The person performing the blood draw will clean the area with antiseptic to help prevent infection.
Then, they’ll wrap your arm with an elastic band to allow the veins to fill with blood and make them more visible. They’ll draw a blood sample using a small needle and then cover the puncture site with gauze or a bandage.
The process takes just a few minutes. The lab will test the blood sample within three to five days. Your doctor will call you with the results.
The normal range for blood chloride is between 96 and 106 milliequivalents of chloride per liter of blood (mEq/L).
A chloride level that’s above normal means there’s too much chloride in your blood, which is called hyperchloremia. A low chloride level indicates that you have too little chloride in your blood, which is called hypochloremia.
Chloride levels that are above normal can be due to:
- medications that treat glaucoma
- bromide poisoning
- metabolic or renal acidosis, which occurs when your body produces too much acid or your kidneys don’t effectively remove acid from your body
- respiratory alkalosis, which occurs when there are low levels of carbon dioxide in your blood
- severe dehydration
Chloride levels that are below normal can be due to:
- heart failure
- excessive sweating
- excessive vomiting
- metabolic alkalosis, which happens when your tissues are too basic (or alkaline)
- respiratory acidosis, which happens when your lungs can’t remove enough carbon dioxide from your body
- Addison’s disease, which happens when the adrenal glands that sit on top of your kidneys don’t make enough of the hormones you need to maintain a normal electrolyte balance
An abnormal level of chloride in your blood doesn’t necessarily mean you have a condition. According to the University of Rochester Medical Center, there are multiple factors that can affect the level of chloride in your blood. Each lab that performs the test may use a different method, which could affect your test results.
Also, how much fluid you have in your system can also affect your results. For instance, a loss of fluid due to vomiting or diarrhea may lower your chloride levels. Speak with your doctor to determine if your test results indicate an issue.
Your follow-up will depend on whether your blood test indicates an abnormally high or low blood chloride level. You can usually correct electrolyte abnormalities that aren’t associated with serious underlying heart, kidney, or liver disease by avoiding certain drugs that may interfere with the absorption of essential substances.
Tell your doctor about any OTC and prescription medications you take. They’ll advise you about which medications you must discontinue, if any.
More serious health conditions, such as heart, kidney, or liver disease, can be related to abnormal blood chloride levels. Early medical intervention may improve the outlook in these cases. Be sure to follow your doctor’s treatment recommendations.