There are many serological diagnostic methods for malaria. This section only introduces the commonly used indirect immunofluorescence test. People who need to be examined: people with obvious chills, body trembling, pale complexion, cyanotic lips, dry skin, irritability, headache, discomfort, anorexia and other symptoms.

Basic Information

Specialist classification: Infectious disease examination and classification: blood examination

Applicable gender: whether men and women apply fasting: fasting

Analysis results:

Below normal:

Normal value:
no

Above normal:

negative:
Negative <1:20, indicating no infection with malaria.

Positive:
The positive detection rate of the fluorescent antibody method is generally higher than the protozoal detection rate. The antibody titer for patients with falciparum malaria is 1:80 or higher and can be considered as a marker for carriers or recent malaria infection.

Tips: Do not eat too greasy, high-protein foods the day before the blood draw, avoid heavy drinking. The alcohol content in the blood will directly affect the test results. After 8 pm on the day before the medical examination, fasting should be started for 12 hours to avoid affecting the test results. Normal value

Negative <1:20.

Clinical significance

The positive detection rate of the fluorescent antibody method is generally higher than the protozoal detection rate. The antibody titer for patients with falciparum malaria is 1:80 or higher and can be considered as a marker for carriers or recent malaria infection.

Positive results may be diseases: malaria, cerebral malaria, lung malaria, malaria

Before inspection:

1, do not eat too greasy, high-protein food the day before the blood, to avoid heavy drinking. The alcohol content in the blood directly affects the test results.

2. After 8 pm on the day before the medical examination, you should start fasting for 12 hours to avoid affecting the test results.

3, should relax when taking blood, to avoid the contraction of blood vessels caused by fear, increase the difficulty of blood collection.

After inspection:

1. After blood is drawn, local compression is required at the pinhole for 3-5 minutes to stop bleeding. Note: Do not rub, so as not to cause subcutaneous hematoma.

2, the pressing time should be sufficient. There is a difference in clotting time for each person, and some people need a little longer to clotting. Therefore, when the surface of the skin appears to be bleeding, the compression is stopped immediately, and the blood may be infiltrated into the skin due to incomplete hemostasis. Therefore, the compression time is longer to completely stop bleeding. If there is a tendency to bleed, the compression time should be extended.

3, after the blood draw symptoms of fainting such as: dizziness, vertigo, fatigue, etc. should immediately lie down, drink a small amount of syrup, and then undergo a physical examination after the symptoms are relieved.

4. If there is localized congestion, use a warm towel after 24 hours to promote absorption.

Inspection process

1. Principle of indirect immunofluorescence test for malaria

The anti-Plasmodium antibody in the test serum is combined with the Plasmodium antigen on the blood slice, followed by the fluorescently labeled anti-human IgG antibody, which acts on the human IgG on the blood slice and exhibits fluorescence at the antigen site.

2, reagents

(1) The antigen blood film is a thin blood film of Plasmodium cynomolgus and a thin blood film of Plasmodium falciparum. Professional research institutions are available. Store in 4 ° C or low temperature freezer.

(2) Fluorescently labeled anti-human IgG, which is commercially available in the country.

3, the operation method

(1) The serum was collected by a conventional method or a circular blot was pressed on the filter paper with a tube of a 1.2 cm diameter glass (iron) tube. Blood is taken from the ear or finger of the subject and filled with a circle. The blood volume is about 20 μl (about 10 μl of serum). After the number is dried, it is placed in a sealed plastic bag with desiccant and transported to the laboratory at 4 ° C. Save for half a year, -20 °C can be stored for 2 years. During the test, the dried blood drops were cut into the wells of the reaction plate, 0.2 ml (pH 7.2) of 0.01 mol/L phosphate buffer was added, and the serum dilution corresponding to 1:20 was obtained by soaking overnight at 4 °C.

(2) Remove the antigen blood film from the refrigerator and immediately blow it dry with an electric fan. Divide each antigen sheet into several small cells with a special crayon. Try 1 specimen or 1 titer per cell, and add 1 serum per cell. drop. Negative, positive reference serum and PBS blank controls were required for each batch of trials. Immediately after adding serum, the mixture was transferred to a wet box, and after incubation at 37 ° C for 30 min, it was slowly washed with 0.01 mol/L PBS (pH 7.2) and then immersed in a PBS cylinder for 5 to 10 minutes.

(3) Dilute the anti-human IgG fluorescent antibody diluted 1:10 with 0.01mol/L PBS (pH 7.2), and place it in the humid chamber at 37 °C for 30 min. After washing with the same method, add glycerol and PBS to each cell. An equal amount of mixed solution or distilled water was applied to cover sheets, and the results of the reaction were examined under a fluorescence microscope.

(4) Interpretation of results: The fluorescence intensity and structure clarity of schizont and trophozoite cytoplasm are distinguished, no fluorescence is (-), fluorescence is weak, morphological structure is unclear (±), fluorescence is weak, and morphological structure It is still clear (+), and is further divided into (2+) to (4+) according to the increase in fluorescence brightness and structural definition.

Generally, the fluorescence intensity (+) or more is judged to be positive at a 1:20 serum dilution.

Not suitable for the crowd

Those who do not have an indication for examination should not do this check.

Adverse reactions and risks

Generally no complications and harm.