The methodologic variables of the UDPG pyrophosphorylase method for analysis of inorganic pyre phosphate (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 p M with a range (M% confidence limits) of 0.58-3.78 pM. Comparison of plasma PPi in normal subjects, patients with primary osteoarthritis, and patients with calcium pyrophosphate dihydrate deposition disease revealed no significant intergroup differences.Measurement of inorganic pyrophosphate (PPi) in plasma and other biologic fluids is important in studies of bone metabolism, renal stone disease, and certain types of arthritis. Previously described methods of PPi

No abstract

No abstract