### **Anti-Chikungunya IgG Antibody Test**
The **Anti-Chikungunya IgG test** is a serological blood assay used to detect Immunoglobulin G (IgG) antibodies, which the immune system produces in response to the Chikungunya virus.
* **Clinical Significance:** IgG antibodies typically appear several weeks after the initial infection and can persist for months or even years, serving as a marker for past exposure or long-term immunity.
* **Diagnostic Utility:** It helps clinicians confirm previous infections, assess the prevalence of the virus in a population, and differentiate Chikungunya from other febrile illnesses like dengue or Zika.
* **Interpretation:** A positive result indicates that an individual was previously exposed to the virus, whereas a negative result suggests no past infection or that the test was performed too early.

### **Anti-Chikungunya IgM Antibody Test**
The **Anti-Chikungunya IgM test** is a crucial serological assay for the early diagnosis of an active or recent infection with the Chikungunya virus. Immunoglobulin M (IgM) are the first antibodies produced by the immune system, typically appearing within 3 to 7 days after the onset of symptoms (primarily fever and severe joint pain).
A positive IgM result indicates a likely current or very recent infection, enabling rapid clinical intervention and public health response. The test is fundamental for differentiating Chikungunya from similar diseases like Dengue, as IgM antibodies typically remain detectable for several months before diminishing.

### **Anti-Hepatitis B Surface Antibodies (Anti-HBs) Test**
The **Anti-HBs (HBsAb) Titre test** is a quantitative blood assay that measures the concentration of protective antibodies against the Hepatitis B surface antigen.
* **Immunity Assessment:** It is primarily used to confirm immunity to the Hepatitis B virus (HBV), acquired either through successful vaccination or recovery from a past, resolved infection.
* **Clinical Threshold:** A titre level of **\ge 10 mIU/mL** is globally recognized as the threshold indicating active, long-term protective immunity against HBV.
* **Pre-employment & Monitoring:** This test is essential for healthcare workers, newborns of HBV-positive mothers, and immunocompromised patients to evaluate their defense status and determine the necessity of vaccine booster doses.