Effect of Hemoglobin-Based Oxygen Carrier-201 on Common Chemistry Laboratory Procedures

Hemoglobin-based oxygen carrier-201 (HBOC) contains a solution of glutaraldehyde-polymerized bovine hemoglobin. The hemoglobin molecule absorbs light at several wavelengths. The presence of HBOC increases plasma and serum hemoglobin, producing the appearance of hemolysis. Young lists >80 analytes for which clinical laboratory tests are affected by hemolysis [1]. In preparation for a multicenter study to evaluate the effect of the use and safety of HBOC (Biopure Corp.), we studied the effect of this drug on most of our instruments and analytes that might be used in management of our patients during the planned clinical trial. The instruments studied were: Abbott AxSym, Bayer DAX, Beckman CX-3 Delta, Dade Dimension, Dade Stratus, Johnson & Johnson Vitros 950, Mallinckrodt GEM Premier, and Nova CRT-16. Samples were prepared from a single serum pool to which increasing concentrations of HBOC (0.0–50 g/L) were added. Of the 30 analytes investigated, only 4 were present in the added HBOC (sodium 153 mmol/L, potassium 4.1 mmol/L, chloride 117 mmol/L, and calcium 70 g/L). Concentrations of these analytes in the unadulterated serum pool were 141, 6.1, and 109 mmol/L and 100 mg/L, respectively. In some instances the effect determined was the sum of the added amount of the analyte and the analytical interference caused by other substances present. The samples were kept at 4 °C until the day of testing. We considered results in the presence of HBOC concentrations to be acceptable if the differences between expected and measured results did not exceed 5% for sodium, potassium, and ionized calcium, 20% for enzymes, and 10% for all other analytes. Results of albumin, bilirubin, gentamycin, γ-glutamyltransfease, lactate, quinidine, and vancomycin were decreased unacceptably when HBOC was present at the lowest concentration tested (0.5 g/L). The acceptable maximum concentrations of HBOC are shown in Table 1 , with the absolute concentration/activity change of each analyte representing the percentage change from the pooled serum according to the above criteria. In 1983, Glick et al. (2) generated “interferograms” to depict the effect of hemoglobin on various chemistry tests; they subsequently expanded their work to illustrate instrument and analyte-specific interferences (3). We generated interferograms to demonstrate our observation that the effect of HBOC on several clinical laboratory tests is instrument- or method-dependent (or both). Some examples are presented in Fig. 1 . This study made it possible toestablish that, because of the availability of various instruments (and methods), we were able to provide sufficient information to our clinicians for the management of their patients during this clinical trial. List of measured analytes, instruments, and acceptable maximum concentrations of HBOC present. ⇓, decrease; ALT, alanine aminotransferase; AST, aspartate transferase; AP, alkaline phosphatase; CK, creatine kinase; LDH, lactate dehydrogenase. List of measured analytes, instruments, and acceptable maximum concentrations of HBOC present. ⇓, decrease; ALT, alanine aminotransferase; AST, aspartate transferase; AP, alkaline phosphatase; CK, creatine kinase; LDH, lactate dehydrogenase. Effect of increasing amounts of HBOC on selected analytes, illustrating method and (or) instrument dependency. As little as 0.5 g/L added HBOC increased the measured albumin concentration and decreased phenytoin beyond acceptable values on the Vitros analyzer but had no effect on the Dimension system. Calcium results were not affected on the DAX, CX-3, and Vitros analyzers. Biopure Corp. reimbursed expenses related to this study.