Transient hyperphosphatasemia is originally described in neonates.

Can also occur in adults and during pregnancy.

There is a marked increase in ALP, often to several thousand IU/L, usually indicating significant pathology.
It is, however, a benign condition with ALP returning to normal in 6-8 weeks.

Transient hyperphosphatasaemia is associated with concomitant infections in over 60% of cases, particularly infections of the gastrointestinal tract.

There is a characteristic pattern in polyacrylamide gel electrophoresis, with the normal pattern of isoenzymes accompanied by variant forms that react with neuraminidase.

It is thought to be due to changes in the carbohydrate side chains causing receptor failure to recognize and reduce clearance, thereby prolonging the half-life.