Gilbert‘s syndrome
Gilbert’s syndrome is a benign congenital defect of glucuronide
conjugation present in up to 5% of the population. It results in an
unconjugated hyperbilirubinaemia which is indicated by the presence of a
high serum bilirubin in the absence of urinary bilirubin (as only
conjugated bilirubin passes into the urine). In Gilbert’s syndrome the
bilirubin level typically increases after fasting and during
intercurrent illness, usually, to a level not exceeding 70 umol/l.
Please note that bilirubin should be >30umol/L for measurement of conjugated bilirubin to be valid. Therefore please do not request conjugated bilirubin testing in patients whose total bilirubin is below this level.
If diagnostic uncertainty remains then genetic analysis for Gilberts
is available. However it is expensive and usually unnecessary. If it
is required, send a single EDTA tube (red/FBC tube) with a
haematology/biochemistry form requesting “Gilbert’s analysis”.
Haemolysis
Haemolysis is conventionally diagnosed by the laboratory appearances
on a blood film, combined with reduced haptoglobin, reticulocytosis and
raised lactate dehydrogenase. There is no clear evidence as to whether
one or all of these tests are required. If evidence of haemolysis is
found, further investigation will be determined by the clinical context,
usually in conjunction with secondary care advice.
