Laboratory parameters of 1st order – obligatory laboratory tests.
- Small blood count; Hb (hemoglobin) and hematocrit (percentage of all cellular components in the volume of blood) are not useful for estimating current blood loss
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate).
- Coagulation parameters – PTT, Quick
- Lactate, if applicable – for risk stratification in patients with suspected gastrointestinal bleeding.
- Test for occult (non-visible) blood in stool (Note “Additional Notes”).
Laboratory parameters 2nd order – depending on the results of the history, physical examination and the obligatory laboratory parameters – for differential diagnostic clarification.
- Stool examination for enteropathogenic germs, fungi, parasites and worm eggs.
- Calprotectin (fecal inflammation parameter; activity parameter; stool sample) – for initial diagnosis and progression of IBD (inflammatory bowel disease), the stool parameter is superior to inflammatory markers in the blood; delineation of noninflammatory causes of gastrointestinal symptoms; normal fecal markers largely rule out active IBD
- Examination of colonoscopy (colonoscopy) biopsies (sampling).
- Liver parameters – alanine aminotransferase (ALT, GPT), aspartate aminotransferase (AST, GOT), glutamate dehydrogenase (GLDH) and gamma-glutamyl transferase (gamma-GT, GGT), alkaline phosphatase, bilirubin.
- Renal parameters – urea, creatinine, cystatin C or creatinine clearance, if necessary.
- Tumor markers:
- Esophagus (food pipe): squamous cell carcinoma antigen (SCC), CEA.
- Stomach: CEA, CA 19-9,
- Colon (large intestine): CEA, tissue polypeptide antigen (TPA), Septin9 test.
Further notes
- A guaiac resin-based fecal occult blood test (gFOBT, Haemoccult test, Haemofec test) is not suitable for the evaluation of gastrointestinal bleeding (false-positive rate of 5-10% and false-negative rate of 30-50%).
