Subnormal alanine aminotransferase values in blood of patients with Crohn disease

It was observed that several patients from the outpatient clinic with Crohn disease (CD) occasionally had subnormal values of alanine aminotransferase (ALAT) in blood. Subnormal ALAT values have previously been reported only in renal failure.

A retrospective study of clinical chemistry values going back 10 years was conducted in all patients from the outpatient clinic with CD or ulcerative colitis (UC). Exclusion criteria were age >50 years, a daily alcohol consumption, known liver disease or other chronic diseases with a possible effect on liver function (n=42). The remaining patients (n=123) were classified as UC, CD or indeterminate colitis (ID). Eight patients with microscopic colitis (MC) were also included.

It was found that 49/50 CD patients had subnormal ALAT on one or several occasions (mean 7 U/L, range 5-9). Only 1/67 patients with UC had subnormal ALAT values. The mean ALAT value in UC was 20 U/L, range 10-40. In IC, 5/6 patients had subnormal ALAT. None of the 8 patients with MC had subnormal ALAT.

The demonstration that subnormal ALAT values are almost entirely seen in CD as compared with UC may have clinical importance and adds to the information on the pathophysiological differences between these two diseases.