Patent ID: 7718356

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 primary isolate with a V3 loop sequencing 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 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 patient-derived (HIV) primary isolate wherein the R5-specific viral load=(VL)(QXR) and the X4-specific viral load=(VL)(1−QXR).