The rapid plasma reaxin loop card assay is a non-specific reaction to serological detection of syphilis. It is used to detect the presence or absence of anti-lipid antigens in the serum of patients, and is often used in screening and epidemiological investigation of syphilis patients.

Basic Information

Specialist classification: Infectious disease inspection and classification: pathogenic microorganism inspection

Applicable gender: whether men and women apply fasting: fasting

Analysis results:

Below normal:

Normal value:

Above normal:


Mainly found in syphilis, the positive rate can reach 80% to 95%.

Tips: Please inform the doctor about the recent medication and special physiological changes before the test. Normal value

1. Qualitative test: negative reaction.

2. Quantitative test: test titer: 1:4 or less.

Clinical significance

Abnormal results:

One of the auxiliary diagnostic methods for syphilis. A known medical history or a person with signs of syphilis. Positive test can be diagnosed as syphilis. After a few weeks of initial infection with syphilis, the titer can be as high as 1:4–1:256. Lupus erythematosus, leprosy, acute infection, autoimmune disease, infectious hepatitis, malaria and rheumatoid arthritis can also be positive, but generally do not exceed 1:8, should pay attention to differential diagnosis.

Need to check the crowd: suspected syphilis patients.

Positive results may be diseases: syphilis, syphilitic cardiovascular disease, congenital syphilis, syphilitic heart disease in the elderly

Pre-inspection requirements:

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.

Requirements for examination: When taking blood, you should relax your mind, avoid the contraction of blood vessels caused by fear, and increase the difficulty of blood collection.

Inappropriate people: generally no special population.

Inspection process

1, laboratory materials


2, the principle of rapid plasma responsive ring card test

The VDRL antigen is adsorbed by the treated activated carbon particles (about 3 to 5 μm). Once this granule antigen binds to the syphilin in the serum, it forms a black clot that can be recognized by the naked eye.

3, reagents

This test has a commercial kit. The RPR antigen suspension is homogeneous, grayish black, and free of impurities. It can be stored for 1 year in the dark at 6~10 °C.

4, the operation method

(1) Qualitative test: 0.05 ml of the test serum (plasma may also be added) to the reaction circle of the special paper card (inner diameter 18 mm), and spread evenly. A calibrated flat-mouth needle (60 ± 2 drops/ml) was used to vertically add 1 drop of RPR antigen suspension to the serum in the reaction zone, and mechanically rotated by hand for 8 min at 100 r/min. See the results with the naked eye in a timely manner. If necessary, tilt the paper jam slightly to help you watch it.

(2) Semi-quantitative test: Take a row of test tubes and dilute the test serum with physiological saline. The rest of the operation is the same as the qualitative test. The highest dilution at which an agglutination reaction occurs is the serum titer of the serum. Report results as follows: Non-reactive (N): The carbon particles are uniformly suspended or concentrated in the center. Reactivity (R): Characteristic carbon black agglomeration occurs regardless of the degree of aggregation. The serum of the reactive results should be further semi-quantitatively tested to indicate its titer.

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.