Stabilities of quantitative plasma culture for human immunodeficiency virus, RNA, and p24 antigen from samples collected in VACUTAINER CPT and standard VACUTAINER tubes.
We evaluated the stability of human immunodeficiency virus (HIV) load markers from blood samples collected in VACUTAINER CPT or standard VACUTAINER brand tubes using sodium heparin or sodium citrate as anticoagulants. Quantitative plasma culture and p24 antigen concentrations were determined, and HIV RNA levels in plasma were measured by both reverse transcription-PCR-enzyme-linked immunosorbent assay (RT-PCR-ELISA) and branched DNA methods. All tubes were stored at room temperature for analysis at 2, 24, 48, and 72 h after the blood samples were drawn. No difference was seen between tube types with respect to the HIV titer in plasma or the positivity rate for all samples that demonstrated a fall in titer over time. Unbound p24 antigen levels in plasma decreased during the initial 48-h period in both tube types. Immune complex-dissociated p24 antigen levels decreased in CPT tubes but not in standard VACUTAINER tubes. The HIV RNA copy number in plasma measured by RT-PCR-ELISA was stable in most subjects and was significantly higher in CPT tubes than in standard VACUTAINER tubes at 24 and 72 h after the blood samples were drawn. The branched DNA probe assay detected a significant decline in HIV RNA equivalent in plasma over 72 h in both collection tubes, the decline being more dramatic in the standard VACUTAINER tube than the CPT tube. Overall, interday variability suggests that samples collected for a particular assay should be processed at the same time after blood is drawn and that a particular tube type be used throughout a given study.
Mole
L
L
ARC-AIDS Research Center, Veterans Affairs Medical Center, Palo Alto, California 94304.
Margolis
D
D
Carroll
R
R
Todd
J
J
Holodniy
M
M
D000925:Anticoagulants; D001800:Blood Specimen Collection / Q000295:instrumentation*; D018791:CD4 Lymphocyte Count; D003470:Culture Media; D004279:DNA, Viral / Q000097:blood*; D016049:Didanosine / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D004797:Enzyme-Linked Immunosorbent Assay; D005069:Evaluation Studies as Topic; D005188:False Negative Reactions; D005782:Gels; D016655:HIV Core Protein p24 / Q000302:isolation & purification*; D015658:HIV Infections / Q000097:blood* / Q000188:drug therapy / Q000382:microbiology; D015497:HIV-1 / Q000254:growth & development / Q000302:isolation & purification*; D006801:Humans; D011091:Polyesters; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D012367:RNA, Viral / Q000302:isolation & purification*; D012720:Severity of Illness Index; D013048:Specimen Handling; D014766:Viremia / Q000382:microbiology*; D014776:Virus Cultivation; D015215:Zidovudine / Q000627:therapeutic use
D000925:Anticoagulants; D003470:Culture Media; D004279:DNA, Viral; D005782:Gels; D016655:HIV Core Protein p24; D011091:Polyesters; D012367:RNA, Viral; D015215:Zidovudine; D016049:Didanosine