Bicarbonate Test

Submitted on March 27, 2012

Bicarbonate (HCO3) is a chemical which prevents the pH levels of the blood from turning too acidic. They are usually prescribed to check for levels of bicarbonate in the blood, for those suffering from certain kidney or lung diseases, or metabolic conditions.

While Bicarbonate loading tests are normally done to check for metabolic acidosis, they are usually tested on blood samples as part of a panel of tests looking at other electrolytes such as potassium, sodium and chloride. Sometimes they are part of an ABG (arterial blood gas) test.

How Bicarbonate test is done

Blood samples for these tests may be taken either from a vein or artery.

If it is from an artery, blood is usually drawn from the radial artery (inside of the wrist), or brachial artery (inside of the elbow) or from the femoral artery (in the groin).

The health professional locates the required pulse, and cleans the site with alcohol. An injection of local anesthesia may be given to numb that area. The needle will then be inserted into the artery and blood will be withdrawn. A sterile cotton ball or gauze pad will be pressed over the site when the needle is removed, and you will be advised to maintain slight pressure on it for an additional 5 to 10 minutes.

Risks involved

Actually, there is very little risk from this test, just some temporary effects.You may feel a little dizzy, faint or light-headed while the blood is being drawn.

  • You may get a small puncture mark or bruise where the needle had been inserted. People with bleeding problems, or those who take blood-thinning medicines like Aspirin or Warfarin, may find that the bleeding does not stop easily.
  • You may get an inflammation at the site of the puncture, but a warm compress usually gives relief.
  • On certain rare cases, the needle may damage an artery or nerve, leading to the artery becoming blocked.

How to prepare for this test

Before going for the blood test, discuss with your doctor if you are on any medicines, especially blood thinners like aspirin or warfarin. Also inform your doctor if you are allergic to any medicines, such as anesthetics which are used to numb the skin.

After the test, apply pressure on the site for at least 10 minutes, or if you have bleeding problems, tie a light bandage.

Refrain from lifting heavy weights or exercising the limb from where blood had been drawn, for at least 24 hours.

Test results

High or low levels of bicarbonate are influenced by various factors.

High levels may be caused by heart disease, chronic obstructive pulmonary disease (COPD), fluid in the lungs, dehydration, vomiting and overuse of antacids (which contain bicarbonate) or diuretics.

Low levels of HCO3 may be caused by kidney or liver disease, uncontrolled diabetes, severe malnutrition, diarrhea, severe burns, hyperthyroidism and overuse of certain medicines or antibiotics.