The incidence and likely origins of serum particulate alkaline phosphatase and lipoprotein-X in liver disease.

Both serum particulate alkaline phosphatase and serum lipoprotein-X have been proposed as diagnostic markers for obstructive liver diseases. In this study their diagnostic efficiencies have been compared with other biochemical indicators of liver function and the relative incidence of these two markers has been determined in 241 patients with well defined liver disease. Although these markers appeared together most frequently in obstructive liver disease they were both present in some patients with liver disorders where obstruction was unlikely. One marker was present, independently of the other in 35% of the patients studied, mainly those without apparent cholestasis. The reasons for this are discussed in terms of the likely origins of the two markers and the probability that serum particulate alkaline phosphatase exists in two forms, as part of a multienzyme plasma membrane complex and as soluble liver enzyme associated with lipoprotein-X.