Iron utilization after iron dextran administration for iron deficiency in patients with dialysis-associated anemia: a prospective analysis and comparison of two agents.

We sought to determine the rate and extent of iron utilization after administration of intravenous iron dextran and to compare the efficacy of iron dextran preparations of differing molecular weight. We randomized patients to receive either a 500-mg dose of iron dextran molecular weight (MW) 267,000 (group A) or iron dextran MW 96,000 (group B) administered in five sequential 100-mg doses, and examined indices of iron status before and at weekly intervals up to 4 weeks later. Although mean iron utilization was greater in the nine group A patients (46.7% +/- 21.3%) than in the 11 group B patients (31.7% +/- 26.6%), the difference was not statistically significant (P = 0.19). Iron utilization in both groups was substantially incomplete. Changes in serum ferritin and hemoglobin did not differ between the treatments (P = 0.49 and P = 0.34, respectively). We conclude that iron utilization after iron dextran administration is substantial within the first week after completing a course of therapy, associated with stable iron indices after the first 2 weeks, and incomplete for at least the first 4 weeks. Degree of iron utilization appears independent of molecular weight within the range we examined.

An undetectable source of technical error that could lead to false negative results in enzyme linked immunosorbent assay of antibodies to HIV-1.

Since the institution of routine testing for antibodies to Human Immunodeficiency Virus (HIV) using the enzyme-linked immunosorbent assay (ELISA), the specificity and sensitivity of this assay system has received significant scrutiny. During previous use of this methodology, we have quantified rates of false biological positive results using commercial kit assays in a normal donor population. In this study, we have identified a potential source for false negative results. Using multiple lots of two different commercial ELISA kits, the absorbance readings at the test end point could not differentiate between normal non-reactive donor samples and blanks containing no sample. These results occur using normal donor samples, even though the assays could distinguish between blank wells and the manufacturers' "normal controls", provided with the assay. Our findings suggest that a technical pipetting error is presently undetectable, either visually or by statistical methods, and could permit an untested, potentially HIV-1 positive, unit to be released into the transfusable blood supply. A possible solution is suggested.

A second discriminator for biological false positive results in enzyme-linked immunosorbent assays for antibodies to human immunodeficiency virus (HTLV-III/LAV).

Two commercially available enzyme-linked immunosorbent assays (ELISA) were compared in screening a large population of volunteer blood donors. One ELISA utilized the human T-lymphotropic virus, Type III (HTLV-III) grown on National Institutes of Health T-lymphocyte cell line, H-9, as antigen source; the second used lymphadenopathy associated virus (LAV) grown on Pasteur Institutes' T-lymphocyte cell line, CEM-F. Biological false positives (BFP) occurred at a rate of approximately 0.5 percent using each antigen source. However, distinct populations of BFP donors were detected when the two antigen sources were compared. Results indicate that at least two separate sets of antigens are recognized in ELISA by our normal population and result in BFP. Sequential utilization of tests using these distinct sources adds a second discriminator to identification of BFP, with the potential for decreasing the requirement for Western blot analysis.

Filtration plasmapheresis in vivo.

A continuous-flow filtration plasmapheresis system has been developed as an alternative to conventional techniques for conducting plasmapheresis from blood donors. The system was tested in two stages, nonreinfusion and continuous reinfusion. Donor safety, separation efficiency, and plasma quality were examined. These studies indicate that membrane plasmapheresis is feasible, safe to the donor, and yields sufficient plasma for either therapeutic or component therapy use.

Abdominal pain in donors during filtration leukapheresis.

An unusual donor reaction characterized primarily by lower abdominal and/or perineal pain occurs in 1.2 per cent of donors during filtration leukapheresis (FL). The reaction occurs almost exclusively in female donors. Corticosteroid pretreatment appears to be highly effective in preventing the reaction. The pathogenesis of this donor problem is speculative.