Laboratory parameters 1st order – obligatory laboratory tests [see below for indications for pathogen diagnostics].
- Stool examinations
- Stool culture: stool for common pathogens (Campylobacter, Salmonella, Shigella, Yersinia), Clostridium difficile, pathogenic E. coli (EHEC, EPEC), Listeria (in neonates), Staphylococcus aureus, sprout fungiIndications: see below.
- Antigen detection (parasites, viruses, toxins): adenovirus and rotavirus antigen detection, detection of Clostridium difficile antigen, verotoxin or Shigatoxin (= toxin enterohemolytic E.coli).
- Microscopic examination for worm eggs, lamblia and amoebic cysts, cryptosporidia, microsporidia.
Laboratory parameters 2nd order – depending on the results of the history, physical examination, etc.
- Small blood count
- Differential blood count
- Inflammatory parameter – CRP (C-reactive protein)
- Electrolytes – sodium, potassium
- Thyroid parameters – TSH
- Renal parameters – urea, creatinine, cystatin C or creatinine clearance, if necessary.
- Pancreatic parameters – amylase, lipase.
- Liver parameters – alanine aminotransferase (ALT, GPT), aspartate aminotransferase (AST, GOT), gamma-glutamyl transferase (γ-GT, gamma-GT; GGT), AP.
- Immunological stool test – exclusion of blood in the stool.
- Calprotectin – clarification of chronic diarrhea.
- Allergen-specific IgE (food allergy).
- Vasointestinal polypeptide (VIP)
- Celiac serology: endomysium antibody (EMA) and transglutaminase antibody (tTG9/ endomysium IgA and transglutaminase IgA – for suspected celiac disease (gluten-induced enteropathy; gluten allergy).
- If necessary, also toxicological tests (see below environmental analysis, drug levels).
- Urine: 5-HIES (5-hydroxyindoleacetic acid due tocarcinoid diagnostics), porphyrins (due tometabolic diagnostics).
- Serology: AK against amoebae, campylobacter, rotavirus, salmonella, shigella, yersinia.
Patients with acute diarrhea in whom pathogen diagnosis is indicated. (mod. by):
- Bloody diarrhea
- Severe clinical picture: high stool frequency, significant dehydration/dehydration of the body (>10% of body weight), “systemic inflammatory response syndrome” (SIRS).
- Immunosuppression
- Relevant comorbidities
- Diarrhea-related hospitalization
- Patients working in community settings or food processing institutions.
- If there is a suspected cluster that suggests an epidemiological link
- After antibiotic use has taken place in the last 3 months.
- Before initiation of antibiotic therapy