Serum adenosine deaminase (ADA)

Adenosine deaminase (ADA) is an important enzyme in the metabolism of purine nucleosides. It belongs to the thiol enzyme and contains at least 2 active sulfhydryl groups per molecule. Its activity can completely inhibit chloromercuric acid. ADA is widely distributed in various tissues of the human body, with the highest content in the thymus, spleen and other lymphoid tissues, and low contents in the liver, lung, kidney and skeletal muscle. The ADA in the blood mainly exists in red blood cells, granulocytes and lymphocytes, and its activity is about 40 to 70 times that of serum. T lymphocytes have higher activity than B lymphocytes.

Basic Information

Specialist classification: Digestive examination classification: biochemical examination

Applicable gender: whether men and women apply fasting: fasting

Tips: After 8 pm on the day before the medical examination, you should fast, so as not to affect the detection of indicators such as blood glucose in the second sky. Normal value

1. Enzyme rate method (37 ° C) healthy adults 7.7-19.3 U / L.
2. Spectrophotometry <25U.
3, colorimetric healthy adults are 5 ~ 25U / ml.

Clinical significance

Increased serum ADA activity is found in:

1 liver disease acute jaundice hepatitis, liver cells appear damaged, before the appearance of jaundice, can be seen increased. Because ADA has a smaller molecular weight than ALT, ADA is released into the blood before ALT when the liver cells are slightly damaged. In the active phase of chronic hepatitis, chronic persistent hepatitis is significantly elevated, and citrus is also elevated in cirrhosis and primary liver cancer.

2 tumor-induced obstructive jaundice, prostate and bladder cancer, reticuloma, lymphoma, hemolytic anemia, rheumatic fever, typhoid fever, gout, severe thalassemia, myeloid leukemia, tuberculosis, autoimmune diseases, contagious Mononucleosis and heart failure can cause this enzyme to rise.

3 Tuberculous pleural and ascites ADA activity was significantly increased, cancerous pleural and ascites did not increase, and serum ADA activity did not differ significantly, so the determination of ADA activity in the chest and ascites helps to identify the two.

4 tuberculous meningitis ADA increased significantly, while viral meningitis did not increase, intracranial tumors and central nervous system leukemia slightly increased. Therefore, cerebrospinal fluid ADA detection can be used as an important indicator for the diagnosis and differential diagnosis of central nervous system diseases.

A decrease in serum ADA activity is found in:

Severe immunodeficiency symptoms.

Low results may be diseases: liver cirrhosis, high results of primary liver cancer may be diseases: severe combined immunodeficiency disease, severe combined immunodeficiency, jaundice hepatitis precautions

1, 0.01mol / L hypochlorous acid solution can be diluted with anti-Fomin solution, the active chlorine content can be calibrated according to the following method: take 2ml of Antefumin liquid, about 20ml of distilled water, 3g of potassium iodide, add glacial acetic acid after dissolution 5ml, with soluble starch (1g / L) as an indicator, titrated with 0.1mol / L sodium thiosulfate, according to its dosage, calculate the concentration of active chlorine in the Anfufu liquid.

2. Replace chloramine T with sodium hypochlorite, and the former has a high effective chlorine concentration and a long reagent storage time. The formula is: NaOH 0.5g, Na2HPO4·12H2O5.37g, chloramine T100mg, add water to 100ml. It can be stored in a brown bottle for 1 year.

3. The distilled water used in the reagents should be deionized water or boiled to reduce the absorbance of the blank tube.

4. The above unit is multiplied by 1.19 to be converted into the international unit concentration (U/L), based on: unit × 1000 / (60 × 14).

5, red blood cells contain a lot of ADA activity, so avoid using hemolysis specimens.

Inspection process

Detection operation: Operate according to Table 1.

Mix well, water bath at 37 ° C for 30 min, at 640 nm, zero with distilled water, read the absorbance of each tube.

Not suitable for the crowd

Inappropriate people: Generally there are no people who are not suitable.

Adverse reactions and risks

Discomfort: There may be pain, swelling, tenderness, and visible subcutaneous ecchymosis at the puncture site.