Usefulness of fecal alpha-1-antitrypsin for detection of gastrointestinal bleeding in patients with gastric cancer.

Hemoglobin (Hb), albumin (Alb), immunoglobulin G (IgG) and alpha-1-antitrypsin (AAT) were measured in 87 fecal samples from 29 normal volunteers and 68 fecal samples from 33 patients with gastric cancer before surgery to evaluate the usefulness of fecal AAT as an indicator of gastrointestinal bleeding in patients with gastric cancer. Mean values and standard deviation of fecal Hb, Alb, IgG and AAT in normal volunteers were 0.13 +/- 1.19 micrograms/g, 6.96 +/- 20.48 micrograms/g, 17.52 +/- 10.16 micrograms/g, and 0.483 +/- 0.315 mg/g, respectively. These parameters in the patients with gastric cancer were significantly higher than those in the normal volunteers. No statistically significant correlations were observed between these fecal parameters, except between fecal Alb and IgG. Data obtained from peripheral blood also showed no significant correlation with these fecal parameters. When the cut-off levels of fecal Hb, Alb, IgG and AAT were set at M + 2SD of the values obtained from the normal volunteers, sensitivity, specificity and accuracy were 80.0%, 86.2% and 84.1% for fecal AAT, and 66.7%, 96.6% and 86.4% for fecal Hb in the patients with advanced gastric cancer in a cohort consisting of patients with advanced gastric carcinoma and normal volunteers. Since fecal AAT showed higher sensitivity in patients with advanced gastric cancer with a low number of false negative cases, we concluded that measurement of fecal AAT could be a promising method for assessment of gastrointestinal bleeding in patients with advanced gastric carcinoma instead of immunological detection of fecal Hb.