Nitroblue Tetrazolium Test

Nitroblue tetrazolium test has been considered as an excellent method of ascertaining difference between pyogenic bacterial infection and other disease processes. The nitroblue tetrazolium test goes to examine if a few immune system cells can transform a colorless chemical called nitroblue tetrazolium (NBT) into a dark blue color.

How Nitroblue Tetrazolium Test is Performed

Blood is generally extracted from a vein, basically from the inner part of the elbow or the back of the arm. The location is made germ free by cleaning it with germ-killing drugs (antiseptic). The health care professional will tie an elastic band on the upper arm to compress the area and enable the vein swell out with blood.

After this, the health care specialist will gradually introduce a needle inside the vein. The blood is collected into an airtight tube linked to the needle. The elastic band is detached from your arm after the session of blood extraction is completed.

Once the blood has been taken, the needle is taken out, and the puncture skin is covered with bandage or a cotton ball and compressed to stop any bleeding.

In infants or small kids, an edged tool called a lancet may be utilized to puncture the skin and allow it bleed. The blood is then collected into a small glass tube often termed as a pipette, or on a slide or test strip. A bandage may be compressed over the area if any bleeding is found.

In the laboratory, the chemical nitroblue tetrazolium is mixed with the extracts of white blood cells. The laboratory professional examines the cells under a microscope and ascertains if the Nitroblue Tetrazolium test made them turn blue.

How to Prepare for the Test

If your child has to undergo this test, it may be important to explain how the test will feel, and it would be even better to demonstrate on a doll. Explain the causes for the test. Knowing the "how and why" may alleviate the anxiety of your child before going through this examination.

How Nitroblue Tetrazolium Test Will Feel

When the needle is introduced into the vein to take the blood, you may feel slight pain, prick or only a stinging sensation. After this you may observe some throbbing sensation.

Why Nitroblue Tetrazolium Test is Performed

This test is conducted to evaluate and study for chronic granulomatous disease. Normally, white blood cells which are also called neutrophils, make special oxygen ingredients that eliminates bacteria. In chronic granulomatous disorder, these compounds are absent. These compounds cause Nitroblue Tetrazolium to transform from clear to deep blue. If they are absent, the white blood cells will remain unaffected and will not change color when NBT is added.

Normal Results

Normally, the white blood cells become blue when Nitroblue Tetrazolium is added. This goes to say that the cells are generating the special oxygen components required to eliminate bacteria. Consult your doctor pertaining to the interpretation of your specific test results.

What Abnormal Results Mean

If the sample is unable to change color when Nitroblue Tetrazolium is added, the white blood cells are not containing the substance imperative to kill bacteria. The cause behind this could be chronic granulomatous disease.

Risks Factors Associated with Nitroblue Tetrazolium Test

There is slight risk witnessed while having your blood taken. Veins and arteries differ in size from one person to another and from one part of the body to the other. Extracting blood from some people may be difficult compare from others.

Other risks factors involved with having blood drawn are mild but may include:

  • Excessive bleeding
  • Feeling of light headedness and fainting feeling
  • Hematoma (blood collection under the skin)
  • Infection (a mild risk of getting the skin broken at any time)

Alternative Names

NBT test


This test is conducted by two different processes and has been re-examined on 223 peoples including healthy people and patients suffering with a wide spectrum of disease. There was a big overlap in the outcomes resulted from controls, patients suffering with pyogenic infection, and patients having other diseases. The test had no symptomatic usability. The Nitroblue Tetrazolium Test outcome in patients suffering with pyogenic infection was found to be associated with the seriousness of the illness. There was poor consent between the results accomplished from the two processes used for the test. Significant observer fault was ascertained in interpretation of the outcomes and this was pertaining to observer experience. The test has not fulfilled its early promise as a simple correct method of ascertaining the difference between bacterial infections from other disease processes.