China is a large country for hepatitis B, and generally speaking, a positive test for hepatitis B surface antigen (HBSAG) indicates the presence of hepatitis B. However, there are exceptions to the exception that a positive HBSAG does not necessarily mean hepatitis B.
So, when is HBSAG positive not necessarily hepatitis B?
First of all, the hepatitis B series (HBSAG, anti-HBS, HBEAg, anti-HBE, anti-HBC, pre-S1 and pre-S2, etc.), hepatitis B virus quantification (HBV DNA) (hypersensitivity detection method), etc. In some places, only HBSAG is checked and other items are not checked, resulting in inaccurate judgment. Based on the results of the above tests or dynamic observation, hepatitis B can be diagnosed or hepatitis B is not supported;
Second, there are the following considerations for HBSAG-positive conditions that do not support hepatitis B (i.e., false positives):
1. Specimen factors, the blood specimen of the examinee has bacterial contamination, hemolysis or severe hyperlipidemia, etc., and there is residual fibrin in the serum;
2. Detection reagent factors, hepatitis B detection reagent expired or unqualified;
3. Operational factors, that is, the factors of operators or inspectors;
4. For their own reasons, there are non-specific interference factors in the examinee's body, such as complement, rheumatoid factor, heterophile antibodies, autoantibodies, etc.
Of course, in this case, the HBSAG titer is generally not too high, and further consultation with a professional doctor or outpatient clinic can be made for further information.