What Is a Chloride Blood Test?

Medically reviewed by Jane Kim, MD

A chloride blood test is a blood test that determines how much chloride is in your body. Chloride is an electrolyte—and electrolytes are electrically charged minerals. They help your body maintain a healthy amount of fluid and balance your pH level.

In most cases, a chloride blood test is part of a routine blood screening to check your general health. Your healthcare provider may recommend checking your electrolytes to evaluate your risk of kidney disease, liver disease, or heart disease. A phlebotomist (a healthcare provider who specializes in blood draws) usually conducts a chloride blood test and sends your sample to the lab for testing. 

Purpose

The purpose of a chloride blood test is to measure the amount of chloride in your blood. Too much or too little chloride could mean that you have a chronic health condition that affects your kidneys, liver, or heart.

Chloride is an electrolyte that affects the balance of fluid and acidity in your blood. Your provider may recommend checking your electrolytes if you have symptoms of a fluid imbalance. These symptoms may include:

• Nausea or vomiting

• Diarrhea

• Trouble breathing 
  

• Fatigue

• Weakness

• Dehydration
  

How Does It Work?

A chloride blood test is usually part of a routine blood screening. You do not need to fast before the blood draw. But, knowing what to expect before, during, and after the test can help you feel prepared when you go in for your appointment.

Before the Test

When you arrive at the clinic or lab for your blood draw, you will check in at the registration desk. You may be asked to fill out a screening questionnaire or sign a consent form. Once it is time for your appointment, a phlebotomist will bring you back to an exam room and show you where to sit. You’ll be asked to place your arm on a desk or table. The phlebotomist may also place a small pillow under your elbow to keep your arm straight.

During the Test

To perform the blood draw, your phlebotomist will wrap a thin rubber strip called a tourniquet around your upper arm. This will feel tight and may be slightly uncomfortable. Once your provider locates a vein, they will use a small needle to puncture the vein and place the needle inside. They will then fill up a tube or syringe with blood. You may feel a pinch or stinging sensation from the needle. But, the entire appointment should take less than five minutes.

After the Test

Once your provider has obtained enough blood for the test, they will remove the needle from your arm and place a cotton ball or piece of gauze over the site. They will press down on the area to help stop the bleeding and then place a bandaid over the area. As long as you are feeling well, you will be free to leave after the test. If you tend to faint or feel lightheaded with blood draws, let your provider know. Do not leave or drive home until you feel back to normal.

When the test is complete, your phlebotomist will send the sample to the lab for testing. A chloride test is usually part of an electrolyte panel that tests the levels of chloride, potassium, and sodium in the blood.

Risks and Precautions

Fortunately, a chloride blood test is considered very low risk. Possible risks include mild pain or bruising at the site. These symptoms usually resolve on their own within a couple of days. 

How To Prepare for a Chloride Blood Test

A chloride blood test is a quick and simple medical test. However, if you're feeling anxious about the blood draw, knowing what to expect may help. Consider the following:

• Location: Your healthcare provider will likely perform the blood draw at an outpatient clinic or lab setting. You may need an appointment or be able to drop in as soon as you’re able.

• Attire: You do not need to wear special clothing for a blood draw. Your provider will likely draw blood from the inside of the elbow, so wear short sleeves or a shirt with loose sleeves.

• Food and drink: Feel free to eat and drink normally before your blood test. If you tend to feel nauseous at the sight of blood, consider not eating right before your test. Drink water as you normally would—as drinking too much or too little water could affect your test results.

• Medications: Ask your healthcare provider if there are any medications that you should stop before a chloride blood test. Taking antacids frequently may sometimes affect your results.

• Items to bring: Plan to bring your insurance card and a photo identification card to your appointment. If there is a long wait, consider bringing a book or something to do.

• Emotional support: If you bring a friend or family member with you, they will be able to sit in the waiting room during your blood draw. Your loved one can drive you home, but if you come alone, it is also safe to drive yourself after the test.

• Cost and insurance: Routine blood screenings are usually covered by insurance. To find out if there will be a copay or fee, consider calling your insurance company and hospital billing department before the appointment.

Results

Results from a chloride blood test are usually ready within 24 hours. If your results are abnormal, your healthcare provider will likely call you to discuss them. If your results are normal, your provider may send the results to you in the mail or through an electronic medical record.

Interpreting Your Results

Too much or too little chloride in the blood may indicate a serious health problem.

A high level of blood chloride may mean you have one of the following health conditions:

• Dehydration: Causes a loss of body fluids, which may produce symptoms like dizziness, headaches, and dry mouth

• Kidney disease: Occurs when the kidneys are damaged or not filtering the blood properly, leading to symptoms like nausea, muscle cramps, and swelling

• Metabolic acidosis: Develops when you have too much acid in the blood, causing symptoms like nausea, vomiting, and fatigue

If your blood chloride levels are too low, it may be a sign of one of these health conditions:

• Heart failure: Occurs when the heart does not pump blood properly, which may cause symptoms like chest pain, shortness of breath, and fatigue

• Lung disease: Develops when the lungs are damaged or are not functioning normally, causing symptoms like trouble breathing

• Addison’s disease: Happens when your body’s adrenal glands do not produce enough hormones, leading to symptoms like weakness, dizziness, weight loss, and dehydration

• Metabolic alkalosis: Causes too much base in the blood, which can lead to symptoms like irritability, muscle twitching, and tingling in the fingers and toes
  

Certain medications may cause abnormal chloride levels.

A Quick Review

A chloride blood test is a routine test that measures how much chloride is in your blood. Chloride is an electrolyte that helps the body to balance fluids and pH levels. During a chloride blood test, a phlebotomist locates a vein on the inside of your elbow, then uses a small needle to draw a sample of blood. They then send the sample to a lab for testing. Too much or too little chloride in the blood may mean that you are at risk of kidney disease, heart disease, or liver disease, among other conditions.

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