Patent ID: 7709191

Claim:
A diagnostic method 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 individual molecular clones of patient-derived HIV primary isolate with a nucleic acid molecule binding assay to determine CCR5 coreceptor usage and CXCR4 coreceptor usage of each individual molecular clone; (b) determining the proportion of HIV using the CCR5 coreceptor (R5) versus the CXCR4 coreceptor (X4) wherein the proportion is expressed as a variable called the Q uantity of X 4 and R 5 (QXR), which represents the fraction of virus in a specimen using the R5 coreceptor; (c) determining coreceptor specific viral loads of the patient-derived (HIV) primary isolate wherein the R5-specific viral load=(VL)(QXR) and the X4-specific viral load=(VL)(1−QXR) wherein the method is used to assess or predict the degree of HIV progression, to determine when to start or change antiretroviral treatment, or to monitor the efficacy of antiretroviral treatment.