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Alanine aminotransferase cut‐off values for blood donor screening using the new International Federation of Clinical Chemistry reference method at 37 °C
Author(s) -
Brinkmann T.,
Dreier J.,
Diekmann J.,
Götting C.,
Klauke R.,
Schumann G.,
Kleesiek K.
Publication year - 2003
Publication title -
vox sanguinis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.68
H-Index - 83
eISSN - 1423-0410
pISSN - 0042-9007
DOI - 10.1046/j.1423-0410.2003.00347.x
Subject(s) - blood donor , alanine aminotransferase , reference range , alanine transaminase , medicine , reference values , chemistry , gastroenterology , immunology
Background and Objectives Serum alanine aminotransferase (ALT) determination is recommended, or even required by law, in the screening of blood donors in many countries, and donors with an increased catalytic activity of ALT are excluded from blood donation. In most countries, the ALT cut‐off value for blood donor screening for men and women is twice the upper limit of the normal range. The introduction, in 2002, of the new International Federation of Clinical Chemistry (IFCC) reference method, performed at 37 °C, required new ALT reference values to be established for healthy individuals and a new cut‐off point to be determined for blood donor screening. Materials and Methods We compared ALT values of donor blood units using the previous German standard method, which measures ALT values at 25 °C, and the new IFCC reference procedure, where ALT levels are measured at 37 °C. Results We found a linear correlation between the ALT values obtained by the method at 25 °C and the new IFCC reference method (37 °C) ( r = 0·983), and a gender‐ and age‐independent ratio of 0·523. Using this ratio we calculated the new ALT cut‐off for blood donations and now propose a new upper limit of 132 U/l (2·20 µkat/l) for men and 86 U/l (1·43 µkat/l) for women. Only 220 of 151 678 blood donations collected over a period of 5 years showed an ALT value higher than the cut‐off. None were hepatitis C virus (HCV) positive in serological or nucleic acid amplification technology (NAT) assays. Only 0·006% of all blood donations were positive for antibody to HCV and thus excluded. Conclusions With the implementation of the new IFCC reference method for ALT determination at 37 °C, we propose a new ALT cut‐off for blood donor screening, which, for men, is about three times the upper limit of the normal range and for women about 2·5 times. Our results show that a lower cut‐off would probably not yield a higher safety of blood products in terms of detecting viral infections, but would result in a loss of ≈ 0·75% of suitable blood donors.