IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C. Part 5. Reference procedure for the measurement of catalytic concentration of aspartate aminotransferase

This paper is the fifth in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37degreesC and the certification of reference preparations. Other parts deal with: Part 1. The Concept of Reference Procedures for the Measurement of Catalytic Activity Concentrations of Enzymes; Part 2. Reference Procedure for the Measurement of Catalytic Concentration of Creatine Kinase; Part 3. Reference Procedure for the Measurement of Catalytic Concentration of Lactate Dehydrogenase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic Concentration of gamma-Glutamyltransferase; Part 7. Certification of Four Reference Materials for the Determination of Enzymatic Activity of gamma-Glutamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37degreesC. A document describing the determination of preliminary upper reference limits is also in preparation. The procedure described here is deduced from the previously described 30degreesC IFCC reference method (1). Differences are tabulated and commented on in Appendix 3.