Preanalytical ammonia generation: a race with time but not with temperature

As recently published by Dukic and Simundic1 in this journal, measurement of reliable ammonia is a real challenge in clinical chemistry. This was brought to the point by Burtis et al (1994) in Tietz Textbook of Clinical Chemistry using the following statement: ‘The key to reliable values from ammonia assays is control of sources of preanalytical error’.2 In this context, the authors discuss that correct ammonia values depend—beside other critical preanalytical conditions—on the activity of γ-glutamyl-transferase (GGT) by hydrolysing glutamine.3 This might be a problem in patients with advanced liver disease due …