IN-VITRO INTERFERENCE OF THE RED-CELL SUBSTITUTE PYRIDOXALATED HEMOGLOBIN-POLYOXYETHYLENE WITH BLOOD COMPATIBILITY, COAGULATION, AND CLINICAL-CHEMISTRY TESTING

Objectives: Pyridoxalated hemoglobin-polyoxyethylene (PHP) is a protot ypical red cell substitute approved for phase I studies. Peripheral bl ood smears of human blood mixed with PHP in 1 to 4 g/dL concentrations showed dose-dependent red cell aggregation and rouleaux. Whether this aggregation limits interpretation of blood compatibility testing and whether the intense coloration of serum or plasma containing PHP affec ts routine coagulation and clinical chemistry measurements was tested. Design: In vitro studies. Setting: University hospital laboratory. Pa rticipants: Four healthy volunteers, blood types A, B, AB, and O. All were Rh+. Measurements and Main Results: ABO typing, Rh typing, and an tibody screening and coagulation studies were performed on blood: PHP admixtures having final concentrations of 1, 2, and 4 g/dL. For clinic al chemistry interference studies, known concentrations of analytes we re added to a serum matrix containing PHP. ABO (forward) and Rh typing showed no interference in the three concentrations tested. Reverse AB O typing and antibody screening showed rouleaux at 4 g/dL, which corre cted with routine saline replacement. Partial thromboplastin time (PIT ), prothrombin time (PT), and fibrinogen showed no clinically signific ant differences from the controls. Results for electrolytes, renal fun ction analytes, and markers of cardiac injury were acceptable by stand ard laboratory methods. However, results of liver function tests were unacceptable in PHP-containing specimens. Conclusions: PHP-induced agg regation was observed with high PHP concentration; however, compatibil ity testing was not affected because agglutination was corrected by sa line replacement, which is standard practice. Although routine blood b anking, coagulation, and most clinical chemistry analytes can be measu red reliably, alternative methods and strategies are needed for assess ing liver function in the presence of PHP. Copyright (C) 1997 by W.B. Saunders Company.