All of the following methods are used for the diagnosis of HIV infection in a 2 months old child, except:

HIV ELISA is required for detection of antibodies against the virus. The antibodies may be present in the infant because of maternal infection also because IgG antibodies can cross the placental barrier. So, this test is not reliable for diagnosis of HIV in a 2 month old child. HIV culture method is called as 'peripheral blood mononuclear cells' (PBMC) using the virus microculture in macrophages concept. PBMC are drawn in high concentration from centrifugation of freshly drawn anticoagulated venous blood. HIV-1 PCR and p24 antigen assay are standard techniques used for viral detection in infants and children. HIV-1 PCR detects both RNA and proviral DNA with sensitivity and specificity of more than 98%.