F2 and hepatitis B virus infection: Other common test results included markers associated with hepatitis B infection (e.g., hepatitis B surface antigen, hepatitis B core antibody, hepatitis B virus DNA; n = 63, 10.0%), body weight (n = 13, 2.1%), serum potassium level (n = 11, 1.8%), blood neutrophil count (n = 10, 1.6%), prothrombin time-international normalized ratio (PT-INR) (n = 9, 1.4%), and serum magnesium level (n = 9, 1.4%).