Coenzyme Q10 be measured in blood plasma, these measurements reflect dietary intake rather than tissue status. Currently, most clinical centers measure CoQ levels in cultured skin fibroblasts, muscle biopsies, and blood mononuclear cells. Culture fibroblasts can be used also to evaluate the rate of endogenous CoQ biosynthesis, by measuring the uptake of C-labelled "p"-hydroxybenzoate. CoQ shares a biosynthetic pathway with cholesterol. The synthesis of an intermediary precursor of CoQ, mevalonate, is inhibited by some beta blockers, blood pressure-lowering medication, and statins, a class of cholesterol-lowering drugs. Statins can reduce serum levels of CoQ by up to 40%. CoQ is not approved by
Reference ranges for blood tests range for a blood test is generally the venous range, as the standard process of obtaining a sample is by venipuncture. An exception is for acid-base and blood gases, which are generally given for arterial blood. Still, the blood values are approximately equal between the arterial and venous sides for most substances, with the exception of acid-base, blood gases and drugs (used in therapeutic drug monitoring (TDM) assays). Arterial levels for drugs are generally higher than venous levels because of extraction while passing through tissues. Reference ranges are usually given as what are the usual (or "normal") values found in