Nitroblue tetrazolium dye test (NTD)
CPT4 code
Name of the Procedure:
Nitroblue Tetrazolium Dye Test (NBT test), Nitroblue Tetrazolium Reduction Test
Summary
The Nitroblue Tetrazolium Dye Test is a diagnostic blood test that measures the ability of white blood cells to produce reactive oxygen species. This test helps in evaluating the functionality of a person's immune system, particularly the neutrophils, which are essential for fighting infections.
Purpose
The test is primarily used to diagnose Chronic Granulomatous Disease (CGD), a genetic disorder that impairs the immune system. The goal is to determine if neutrophils can adequately produce the oxidative burst needed to kill certain bacteria and fungi, which helps in diagnosing CGD.
Indications
- Recurrent bacterial and fungal infections
- Symptoms suggestive of weakened immune function
- Family history of Chronic Granulomatous Disease
- Unexplained infections in unusual locations or with unusual organisms
Preparation
- No special preparation is usually required.
- Patients may be advised to inform the healthcare provider about any medications they are taking.
- Routine blood tests may be conducted beforehand to assess overall health.
Procedure Description
- A blood sample is drawn from the patient, typically from a vein in the arm.
- The sample is mixed with a nitroblue tetrazolium (NBT) dye.
- If neutrophils are functioning normally, the dye is reduced, forming a blue precipitate.
- The sample is then examined under a microscope to assess the presence of the blue dye, indicating normal neutrophil function.
Duration
The test itself takes only a few minutes for the blood draw; results may take a few hours to a day.
Setting
The procedure is performed in a hospital laboratory or outpatient clinic.
Personnel
- Phlebotomist or nurse to draw the blood sample
- Laboratory technician or medical technologist to analyze the sample
Risks and Complications
- Common: Minor discomfort or bruising at the blood draw site
- Rare: Infection or excessive bleeding at the puncture site
Benefits
- Accurate diagnosis of Chronic Granulomatous Disease
- Helps in guiding appropriate treatment and management of the patient's condition
Recovery
- Minimal recovery required as it is a simple blood test.
- Patients can resume normal activities immediately after the blood draw.
Alternatives
- Dihydrorhodamine 123 (DHR) test, which is more sensitive and can also diagnose CGD.
- Genetic testing to identify mutations associated with CGD.
- Each alternative has its own advantages and limitations; a healthcare provider can guide which test is most appropriate.
Patient Experience
- Patients might experience a brief sting or discomfort during the blood draw.
- Minor soreness or bruising at the puncture site may occur.
- Overall, the procedure is quick and typically well-tolerated.