CRP and alkaline phosphatase measurement: When HO was suspected, both AP and CRP showed elevated values with a median of 163 (IQR = 114–305) U/l (normal: 35–105 for females and 40–130 U/l for males) for AP and 22 (IQR = 17–39) mg/l (normal: <5 mg/l) for CRP.