Hepatitis A is caused by hepatitis A virus (HAV). There are two types of antibodies (anti-HA) in serum, namely anti-HAIgM and anti-HAIgG. Anti-HAV-IgG appears later and lasts longer and is often negative at the beginning of the infection. It is commonly used in epidemiological investigations. Anti-HAIgM positive can be diagnosed as hepatitis A. If low titer is detected, it should be retested every 2 weeks, but attention should be paid to false positive caused by rheumatoid factor.

Basic Information

Specialist classification: Infectious disease examination and classification: immunological examination

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

Analysis results:

Below normal:

Normal value:
no

Above normal:

negative:
normal.

Positive:
Prompt that there may be viral hepatitis.

Tips: If a low titer is detected, it should be retested every 2 weeks. Normal value

Anti-HAIgM negative.

Clinical significance

Anti-HAIgM positive can be diagnosed as hepatitis A. If low titer is detected, it should be retested every 2 weeks, but attention should be paid to false positive caused by rheumatoid factor. Anti-HAIgG positive suggestive of HAV infection, but the double anti-HAIgG titer increased more than 4 times, also has diagnostic significance.

Precautions

When testing:

Anti-HAV-IgG appears later and lasts longer and is often negative at the beginning of the infection. It is commonly used in epidemiological investigations. Anti-HAIgM positive can be diagnosed as hepatitis A. If low titer is detected, it should be retested every 2 weeks, but attention should be paid to false positive caused by rheumatoid factor. Anti-HAIgG positive suggestive of HAV infection, but the double anti-HAIgG titer increased more than 4 times, also has diagnostic significance.

Inspection process

Anti-HAVIgM: Hepatitis A-specific antibody-(anti-HAVIgM) appears early, usually can be detected on the day of onset, peaking in the jaundice period, antibody titer decreases from January to February, most disappear from March to April . It is an important indicator for early diagnosis of hepatitis A. Commonly used methods are enzyme-linked immunosorbent assay (ELISA) and solid phase radioimmunoassay (SPRIA), which have high sensitivity and specificity. A routine item for the detection of patients with acute hepatitis. Rheumatoid factor-positive specimens may exhibit anti-HAVIgM false positives and should be noted.

Anti-HAV IgG: When symptoms appear in patients with acute hepatitis A, anti-HAV IgG can be detected in the serum, the initial titer is low, and then gradually increases, peaking in March after the disease, maintaining a high level in 1 year, low level It can last for decades or even life in the blood. For example, the anti-HAV IgG titer of the double serum can increase the serum of the recovery period by more than 4 times, and the hepatitis A can be diagnosed. Often because of the late patient visit, the early serum is not harvested, and the antibody titer is not increased by 4 times. Therefore, this diagnostic method is basically not used clinically. Anti-HAV IgG is used to detect epidemiological investigations of population immunity.

HAV-RNA utilizes cloned HAV cDNA fragments to make probes, and cDNA-RNA hybridization technology can be used to detect HAV-RNA in serum and feces of acute hepatitis A. Since the application of polymerase chain reaction (PCR) in clinic, A more sensitive method for detecting HAV-RNA. The reverse transcription-PCR (RT-PCR) method was used to convert HAV-RNA into cDNA using reverse transcriptase, followed by PCR detection. Positive for HAV-RNA, direct evidence of acute infection with HAV.

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Adverse reactions and risks

There are no related complications and hazards.