Alkaline Phosphatase Isoenzymes
1) Investigation of suspected transient hyperphosphatasaemia of
childhood. This may occur in some younger adults.
2) In other patients, isoenzyme analysis may, rarely, be useful
to investigate the origin of an unexplained elevated alkaline
3) Abnormalities in liver function tests may occur during normal
pregnancy (probably due to increased level of oestrogens) and
levels of gamma-GT and alkaline phosphatase (ALP) rise in late
pregnancy; the latter mainly due to placental (heat-stable) ALP.
The most pronounced change is a tendency towards cholestasis in the
last trimester and in a small percentage of women symptoms of
jaundice/pruritus develop (intrahepatic cholestasis of
serum bile acids may be useful and very occasionally, it
may be necessary to determine whether a raised ALP level is of
placental or liver origin.
Request on ICE
On request, after discussion with a Clinical Biochemist
Investigation of unexplained elevated alkaline phosphatase in
childhood. Differentiation of placental alkaline phosphatase from
liver in suspected intrahepatic cholestasis of pregnancy. Other
requests must be agreed with Consultant Biochemist.
Serum in gold-top vacutainer
Sent to referral laboratory (Great Ormond Street)
No specific collection conditions
Aliquot and store at 4C.
Causes for Rejection
Normal alkaline phosphatase level. Unlabelled or
incorrectly labelled sample