title: Quantification of human plasma inorganic pyrophosphate. I. Normal values in osteoarthritis and calcium pyrophosphate dihydrate crystal deposition disease.
abstract: The methodologic variables of the UDPG pyrophosphorylase method for analysis of inorganic pyrophosphate (PPi) levels in biologic fluids are described. Use of a tourniquet in collection of blood specimens elevated plasma PPi levels from 35% to 55% above control values and may explain the differences in published normal values. The sodium pyrophosphate decahydrate used to prepare the standard solution lost 8 waters of hydration after dessication, which could result in the calculation of spuriously elevated PPi levels. Normal plasma PPi concentration was 2.18 muM with a range (95% confidence limits) of 0.58-3.78 muM. Comparison of plasma PPi in normal subjects, patients with primary osteoarthritis, and patients with calcium pyrophosphate dihydrate deposition disease revealed no significant intergroup differences.
mesh_terms: D001800:Blood Specimen Collection; D002131:Calcium Pyrophosphate / Q000097:blood*; D002805:Chondrocalcinosis / Q000378:metabolism*; D011756:Diphosphates / Q000097:blood*; D006801:Humans; D008722:Methods; D010003:Osteoarthritis / Q000378:metabolism*; D014111:Tourniquets
chemical_list: D011756:Diphosphates; D002131:Calcium Pyrophosphate