Hepatitis B virus (HBV) genotyping is a laboratory test used to determine the specific genotype or strain of the virus present in a patient’s blood. The test is done by analyzing the genetic material of the virus found in the blood sample. There are eight different HBV genotypes identified (A-H), with different geographic distributions and varying clinical outcomes. Knowing the genotype of the virus can help guide treatment decisions and predict the likelihood of disease progression. For example, some genotypes are more responsive to certain antiviral medications than others. The HBV genotyping test is typically done in specialized laboratories and is recommended for patients with chronic HBV infections, as well as those who have failed to respond to standard treatments. Overall, HBV genotyping is an important tool in the management of HBV infections and can help improve patient outcomes by tailoring treatments to the specific genotype of the virus.