You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Test used for diagnosis of HIV infection during window period - and explain in detail?
Ans. is 'a' i.e., p-24 antigen * P-24 antigen is the earliest virus marker to appear in blood and is the one tested for.* It may be detectable in blood after about 2 weeks.Laboratory diagnosis of HIV infection* Laboratory diagnosis is made by:A) Antibody detection# It is the most common method used for diagnosis of HIV infection.# ELISA is the most sensitive test and therefore is the serening test of choice.# Western blot is the most specific (Confirmatory) test and therefore is the 4gold standard* for diagnosis,# Antibodies test usually become positive 22 days after the infection.B) Detection of HIV nucleic acid or antigen# p24 antigen detection by ELISA can be done 16 days after infection (earlier than antibody detection).# Nucleic acid detection tests are the earliest to become positive (12 days after infection). Most commonly used test is reverse transcriptase PCR, (RT-PCR). Other methods used are DNA-PCR, RNA-PCR, RNA- bDNA (branched DNA), and RNA-NASBA (nuclei acid sequenced based assay).C) Virus isolation# Co-cultivation of the patient's lymphocyte with uninfected lymphocytes in the presence of IL-2# Not suitable as a routine diagnostic procedure.In infected individual HIV can be isolated from :* Blood* Semen* Saliva* Urine* Lymphocytes* Cervical secretions* Tears* Breast milk