EXTRACTION AND QUANTIFICATION OF ANTI-HLA ANTIBODIES FROM WHOLE BLOOD SAMPLES COLLECTED WITH THE PRA-STAT-BCD™ AT HOME FINGERSTICK COLLECTION DEVICE.

Abstract

683 Panel Reactive Antibody (PRA%) provides an indication of the level of sensitization of a potential transplant recipient to the HLA allotypes of the potential donor pool. PRA% is often used as one of the many factors in determining a patient's wait time for an organ. High PRA% as determined by PRA-STAT can also indicate an increased likelihood of a rejection episode after kidney transplantation. For these reasons, pretransplant monitoring of PRA% is conducted on a regular basis throughout a patient's time on a transplant waiting list; this may be a period of several years. Purpose: To demonstrate the feasibility of an at home sampling device for the measurement of PRA% using venous whole blood as an experimental substitute for fingerstick blood samples. This device is designed to accept a whole blood sample self-collected at home by a patient from a fingerstick. The sample would then be sent to a central testing facility, where the PRA antibodies would be extracted and measured, and the result reported to the patient's physician. Method: A total of 16 venous-EDTA samples were obtained from patients on a kidney transplant wait list. Samples were stored at 2-8°C until testing, and which time they were separated into 2 aliquots. Serum was separated from one aliquot by centrifugation. The resultant serum sample was analyzed using the PRA-STAT ELISA (SangStat Medical Corporation). The other aliquot of the venous samples were sampled as whole blood with the PRA-STAT-BCD fingerstick sample collection device. The device remained at 20°C overnight, at which time PRA anti-bodies were extracted and analyzed with a modification of the PRA-STAT ELISA. Results: Samples were tested in duplicate by both methods. The correlation between the methods was excellent, with a slope of 1.01 and an R=0.98. Qualitative reproducibility of the duplicate values was 94% for the serum samples and 100% for the whole blood fingerstick device samples. (Figure)FigureConclusion: These studies demonstrate the feasibility of a device for at home collection of samples for PRA% determinations.