Best method to diagnose HIV in an infant?

c. PCR(Ref: Update on antiretroviral regimens for treating and preventing HIV infection and update on early infant diagnosis of HIV July 2018 policy brief HIV treatment-interim guidance)WHO recommends that HIV virological testing (HIV DNA or RNA PCR or HIV culture) be used to diagnose HIV infection among infants and children younger than 18 monthsIn any child > 18 mo of age, demonstration of IgG antibody to HIV by ELISA & Western blot test establishes HIV infection