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General Guideline: Processing a specimen containing HBOC (Hemopure or Oxyglobin)

• Determine whether or not your laboratory has generated its own HBOC interference data.
• The IVD manufacturer of the laboratory instrument also may have information on how HBOCs affect individual assay results (See Existing Data: IVD Manufacturer Data page).
• If neither choice is available, there are two other alternatives:
  1. Use the Hemopure interference data that was collected from human clinical laboratories. The Laboratory Director or other responsible personnel at your hospital must determine whether or not such summary data are useful for your hospital (See Existing Data: Clinical Trial Information page).
  2. Do not permit assays that may be influenced by an HBOC to be run until the HBOC has been cleared from the patient's blood and specimens are no longer discolored. General information on the following laboratory tests are:

     Cardiac Markers

     • Instruments vary in the degrees of interference observed and no generalizations can be made.

     Chemistry Assays

     • The hemolytic index provided by the manufacturer of the instrument may be useful as a conservative criterion for obtaining accurate HBOC concentrations and flagging inaccurate results. 1
     • In general, if HBOC is present:
       
       

       Analyte	Comment
       Chloride, Sodium, Potassium	Accurate up to a maximum HBOC concentration of 6.5 g/dL*
       Creatinine	Interferences can be overcome by pre-filtering the specimen (i.e., appropriate 100 kD filters [Amicon Ultra-4 Ultracel - 100k, Cat# UFC810096, Millipore Corporation, Billerica, MA 01821, www.millipore.com]) or deproteinization of the specimen to remove the HBOC and permit an accurate measurement of the analyte. 2
       Albumin, Alkaline phosphatase, Bilirubin	Not accurate
       All other chemistry analytes	Dependent upon the instrument and generalizations are not possible.

       *concentrations greater than 6.5 g/dL have not been evaluated

     Coagulation

     • Prothrombin (PT) and activated partial thromboplastin time (aPTT) can be determined accurately using methods that are mechanical, magnetic and light scattering. Optical methods show variable degrees of interferences.

     Co-oximetry and Blood Gas Tensions

     • Oxygen saturation values may be decreased due to the right shifted oxygen equilibrium curve of HBOC compared with native red blood cells. This is an expected effect and the reading is accurate.
     • The partial pressure of gases such as oxygen and carbon dioxide are accurate.

     Hematology

     • All hematology measurements (RBC, WBC and platelet counts, RBC and WBC differentials) are accurate.
     • Measurements that rely on hemoglobin (i.e., MCHC) will be affected since HBOC will be part of the hemoglobin measurement.

     Therapeutic Drug

     • Instruments vary in the degree of interferences observed with HBOC-201 and no generalizations can be made.

     Transfusion medicine

     • HBOCs do not affect blood typing.
     • For cross-matching, agglutination should be used as an endpoint because HBOCs will mimic hemolysis and may confound results.

     Urinalysis

     • PHYSICIANS: Hemopure® is not cleared through the kidney and thus there should be no Hemopure present in the urine. Tests are accurate. If there is bleeding into the urinary system, and thus potential for Hemopure to be present in the urine, dipstick results will be inaccurate. Sediment examination is valid to establish the presence of cells.
     • VETERINARIANS: A small portion of Oxyglobin IS cleared through the kidneys and thus tests are NOT accurate until the urine contains no free hemoglobin.
• For more detailed information, please see our Detailed Instructions page.

References:
1. Callas DD, Clark TL, Moreira PL, Lansden C, Gawryl MS, Kahn S, Bermes EW. In vitro effects of a novel hemoglobin-based oxygen carrier on routine chemistry, therapeutic drug, coagulation, hematology, and blood bank assays. Clin Chem. 1997;43(9):1744-1748.

2. Moon-Massat PF, Tierney JP, Hock KG, Scott MG. Hitachi Hemolytic Index correlates with HBOC-201 concentrations: Impact on suppression of analyte results. Clin Biochem. 2007 Dec 23; [Epub ahead of print].

For more detailed information, please see our Detailed Instructions page.