Document 3052
 DOCN  M94A3052
 TI    Reducing the variation in CD4 lymphocyte count measurements.
 DT    9412
 AU    Raboud JM; Haley L; Montaner JS; Murphy C; Januszewska M; Schechter MT;
       Univ of British Columbia, Vancouver.
 SO    Int Conf AIDS. 1994 Aug 7-12;10(1):164 (abstract no. PB0082). Unique
       Identifier : AIDSLINE ICA10/94369523
 AB    OBJECTIVE: To quantify the variation in CD4 counts of HIV infected
       individuals due to laboratory and physiological factors and to find
       strategies to reduce variation. METHODS: Blood was drawn from 30 HIV +ve
       clinically stable men 3 times in each of 2 weeks, 4 weeks apart. At each
       visit, 2 tubes of blood were drawn. Duplicate measurements were
       performed on one of the blood samples. RESULTS: The coefficients of
       variation of CD4 counts due to physiologic and laboratory factors were
       13.3 (95% CI: 12.0, 15.1) and 5.6 (95% CI: 5.2, 6.1) respectively. Thus
       laboratory factors accounted for 15% of the variation between visits.
       Variation in the absolute WBC, lymphocyte % and CD4% accounted for 52%,
       29% and 19% of the physiologic variation in CD4 counts respectively.
       CONCLUSIONS: Our results confirm a high degree of variability of CD4
       counts among HIV infected individuals, largely attributable to
       physiological factors. This variability can be minimized more
       effectively by repeating CD4 counts over time than by repeating
       measurements at a single visit. Our data further suggest that the
       variability of CD4 counts can be reduced by 80%, and at lower cost, if a
       single CD4 fraction is utilized with the lymphocyte count repeated over
       time.
 DE    Adult  Human  HIV Seropositivity/CLASSIFICATION/DIAGNOSIS/*IMMUNOLOGY
       *Leukocyte Count  Male  Quality Control  Reproducibility of Results  T4
       Lymphocytes/*IMMUNOLOGY  MEETING ABSTRACT

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       protected by Copyright Law (Title 17, U.S.Code).