The specific polysaccharide of group A hemolytic streptococcus cell wall has cross-antigenicity with human heart valve glycoprotein. When group A hemolytic streptococcus is infected into human body, it can stimulate the body to produce anti-streptococcal polysaccharide (ASP). The action of this antibody on a human heart valve can cause damage to the valve, causing rheumatic heart valve disease. It has been measured that the most biologically active part of the antigen is 38KD, and the values ​​of IgG and IgM can be detected by ELISA, which is easy to be clinically popularized. Since the level of this antibody can better reflect the damage of heart valve, this antibody can not only support the existence of previous streptococcal infection and the current autoimmune reaction of acute rheumatic fever, but also predict the prognosis of rheumatic fever, so it is clinically Has a large reference value.

Basic Information

Specialist classification: cardiovascular examination classification: immune examination

Applicable gender: whether men and women apply fasting: not fasting

Analysis results:

Below normal:

Normal value:
no

Above normal:

negative:
normal.

Positive:
Prompt rheumatic heart valve valvitis.

Tips: False negative can be seen in the early use of antibiotics or hormone therapy in patients. Normal value

ASP-IgG (1.334 ± 0.578) BI; ASP-IgM (1.011 ± 0.315) BI. Binding index (BI) = (assay specimen A - non-specific binding A) / (normal serum A - non-specific binding A). If the mean value of the normal control group plus 2 standard deviations is the upper limit of normal value (ULNV) to determine positive and negative, then normal is negative.

Clinical significance

(1) Patients with rheumatic valvular heart disease have elevated serum ASP and have a longer duration. The level of ASP in patients with rheumatic fever without valvular lesions is lower, and the level of ASP in patients with rheumatic heart disease with increased ASP after pathological resection of the disease It then falls, so ASP is considered to have the specific diagnostic significance of the valve.

(2) The positive rate of ASP in patients with rheumatic valvular heart disease is above 80%, while the positive rate of other non-rheumatic valvular heart disease, streptococcal infection status, acute nephritis and viral myocarditis is 10% to 13%.

(3) Dynamic observation of rheumatic valvular heart disease showed that the level of ASP-IgM decreased rapidly with the improvement of the disease, while ASP-IgG continued to be high for a long time. ASP-IgM can be used as a monitoring condition and guiding treatment. Sensitive indicators.

(4) Compared with other traditional indicators, ASP is far superior to ESR and CRP in the activity of rheumatoid carditis, and is far superior to ASO in the immune response after Streptococcus infection. Therefore, ASP assay has specificity. Has diagnostic value for activity.

Precautions

The patient's serum may contain some blood-staining substances or blood-stained bacteria, and hypercholesterolemia may cause false positives; false negatives may be seen in the early use of antibiotics or hormones in patients.

Inspection process

Same as ELISA.

Not suitable for the crowd

There are no taboos.

Adverse reactions and risks

There are no related complications and hazards.