1st-order laboratory parameters-obligatory laboratory tests.
- Small blood count
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate).
- Electrolytes – potassium, magnesium, sodium.
- Fasting glucose (fasting blood sugar)
- Renal parameters – urea, creatinine, cystatin C or creatinine clearance, if necessary.
- Coagulation parameters – activated partial thrombin plastin time (aPTT), anti-factor Xa activity (aXa), ecarin clotting time (ECT), INR (International Normalized Ratio), Quick value, thrombin time (TC).
Laboratory parameters 2nd order – depending on the results of the history, physical examination, etc. – for differential diagnostic clarification.
- Drug screening
- Ethanol (ethanol; marker for acute alcohol abuse).
- Blood cultures (BK; at least three at intervals of at least 60 min; allow BK to incubate for at least 2 weeks! Collection regardless of fever due tocontinuous bacteremia) – if endocarditis (endocarditis) is suspected.
- CSF puncture (removal of nervous fluid by puncture of the spinal canal) for CSF diagnostics – on suspicion of cerebral hemorrhage with intrusion into the ventricular system (cavity system in the brain) (intraventricular hemorrhage (IVB)) or subarachnoid hemorrhage (SAB).
- Vasculitis diagnostics (see below “Vasculitides“).
Notes on the selection of blood coagulation parameters:
- Basic diagnostics: aPTT (activated partial thromboplastin time) and INR (International Normalized Ratio); if therapy is given with
- Vitamin K antagonists: INR determination
- Full heparin: aPTT
- Low-molecular-weight heparins (NMH)/heparin analogues: compound-specific anti-Xa activity required.
- NOAKs (new oral anticoagulants).
- Dabigatran: thrombin time and dabigatran concentration required.
- Factor Xa inhibitors: compound-specific anti-Xa activity (apixaban, edoxaban, rivaroxaban) required (note: low sensitivity with apixaban.
