2nd order laboratory parameters – depending on the results of the history, physical examination and obligatory laboratory parameters – for differential diagnostic workup
- Small blood count [leukocytosis (increase in white blood cell count): infection; anemia (anemia): secondary headache as anemia symptom; thrombocytopenia (decrease in platelets/platelets): increased cerebral bleeding risk].
- Inflammatory parameters – CRP (C-reactive protein) [sign of infection?]
- Electrolytes – calcium [hypercalcemia (excess calcium): bone metastases]
- Fasting glucose (fasting blood glucose).
- Renal parameters – creatinine [creatinine elevation in desiccation/dehydration], cystatin C if necessary.
- Blood gas analysis (BGA)
- CSF puncture (collection of cerebrospinal fluid by puncture of the spinal canal) for CSF diagnosis – in case of suspected meningitis (meningitis)/meningoencephalitis (combined inflammation of the brain (encephalitis) and meninges (meningitis)) and subarachnoid hemorrhage (SAB).