Patent ID: 8119339

Claim:
A method of determining whether to initiate antiretroviral therapy in a patient comprising determining the viral load of a population of human immunodeficiency virus (HIV) using the CXCR4 coreceptor (X4-specific viral load) in a patient-derived biological sample comprising the steps of: (a) screening the patient-derived biological sample to determine the CCR5 coreceptor usage and the CXCR4 coreceptor usage of individual HIV within the population of HIV; (b) determining the proportion of HIV using the CCR5 coreceptor (R5) versus the CXCR4 coreceptor (R4) wherein the proportion is expressed as a variable called the Quantity of X4 and R5 (QXR), which represents the fraction of virus in a specimen using the R5 coreceptor; (c) determining coreceptor specific viral loads of the population of HIV wherein the R5-specific viral load=(VL)(QXR) and the X4-specific viral load=(VL)(1−QXR); wherein an X4-specific viral load is greater than zero indicates a need to initiate antiretroviral therapy in the patient.