Higher HIV-1 RNA cutoff level required in cerebrospinal fluid than in blood to predict positive HIV-1 isolation.
HIV-1 can be isolated from the vast majority of blood samples taken from HIV-1-seropositive patients not treated with antiretroviral drugs. Isolation rates from cerebrospinal fluid (CSF) samples are considerably lower, ranging between 20-70%. The objective of this study was to determine the cutoff levels for HIV-1 RNA that would yield a positive predictive value > or =90% for positive virus isolation from CSF and blood. Quantitative HIV-1 RNA PCR (Amplicor HIV monitor, version 1.0, Roche Diagnostic Systems) and virus isolation were used to examine 303 CSF samples and 278 paired blood samples from 157 HIV-1-seropositive patients. Patients on antiretroviral treatment provided 140 of the CSF samples and 131 of the blood samples. CSF samples that were positive by culture numbered 137 of 303 (45%), as compared with 216 of 278 (78%) blood samples. In the case of samples taken from patients with antiretroviral treatment, 28% were positive by culture from CSF and 63% from blood. As expected, mean HIV-1 RNA levels were higher in CSF and blood samples positive by culture than in samples negative by culture. A cutoff level of >5,000 HIV-1 RNA copies/ml was required to yield a positive predictive value for positive virus isolation from CSF samples of > or =90%, whereas the cutoff level for blood samples was just above the detection limit of the assay (>200 HIV-1 copies/ml).
Andersson
L M
LM
Institute of Internal Medicine, Department of Infectious Diseases, Göteborg University, Sahlgrenska University Hospital, Sweden. lars-magnus.andersson@medfak.gu.se
Svennerholm
B
B
Hagberg
L
L
Gisslén
M
M
D000163:Acquired Immunodeficiency Syndrome / Q000175:diagnosis / Q000276:immunology / Q000821:virology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D018791:CD4 Lymphocyte Count; D005260:Female; D006679:HIV Seropositivity / Q000097:blood / Q000134:cerebrospinal fluid; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011237:Predictive Value of Tests; D012367:RNA, Viral / Q000097:blood / Q000134:cerebrospinal fluid; D012680:Sensitivity and Specificity
D012367:RNA, Viral