Anyone who works in a special coagulation laboratory has received an isolated order for protein C. A protein C activity assay alone makes little sense, and we know the order was probably erroneous. This is our fault for using confusing test names.
Is it protein C, activated protein C resistance (APCR), or C-reactive protein? These are fine naming distinctions for those who don’t work with this information every day.
Activated protein C resistance (APCR) is commonly ordered, and screens for the factor V Leiden mutation, a common thrombosis risk factor in Caucasians. It may be ordered alone, but is more often part of a thrombosis risk profile that includes…
Protein C activity
Protein S activity
Prothrombin 20210 mutation assay
Lupus anticoagulant test profile
Beta-2-glycoprotein 1 assay
Protein C deficiency is also a thrombosis risk factor, but is typically ordered in a profile as listed above.
C-reactive protein is an assay that detects and monitors chronic and acute inflammation. When elevated in chronic inflammation, C-reactive protein predicts cardiovascular disease.
So for most of us in the lab, an isolated protein C assay order should prompt a call to determine exactly what assay was desired. Geo.