Page 116 - 16Neonatal Jaundice_compressed

6 Formal assessment for the

causes of neonatal

hyperbilirubinaemia

Introduction
Most babies with an elevated serum bilirubin level do not have underlying disease, and the
jaundice resolves by 2 weeks of age. However, an important minority have a diagnosis that
requires specific treatment. Babies who have haemolysis (rapid breakdown of red cells) because
of antibodies or G6PD deficiency can have rapidly rising bilirubin levels that are difficult to
control even with phototherapy. The correct diagnosis of ABO blood group incompatibility has
implications for future pregnancies, and G6PD deficiency can affect other family members. In
babies with prolonged jaundice, a late diagnosis of biliary atresia significantly reduces the
chance of successful surgery and increases the chance of a liver transplant being required. For
all these reasons, further investigation has to be considered in some cases.

Current practice regarding the level of investigation that is carried out in babies who are
jaundiced varies enormously, particularly with regard to concern about bacterial sepsis and the
use of antibiotics. The GDG considered that it was important to examine the evidence in order
to determine the appropriate investigations that should be performed, and in which groups
(mild, moderate and severe hyperbilirubinaemia, and early and prolonged jaundice).

Clinical question
Q4. What should be included in a formal assessment of a baby with neonatal
hyperbilirubinaemia?
i) What are the elements of a formal assessment in a baby with neonatal
hyperbilirubinaemia?
a) Clinical examination
b) Total and split bilirubin
c) Blood tests – blood grouping, G6PD levels, haematocrit,
d) Urine tests
e) Biochemical tests (bilirubin/albumin ratio, other relevant tests)
ii) What is the clinical and cost-effectiveness of the tests carried out during formal
assessment?

In order to identify possible causes of neonatal jaundice according to the severity of
hyperbilirubinaemia, it was decided to include only those studies that met the following
predefined selection criteria:
● studies with well-defined serum bilirubin levels as cut-off for entry into the study
● studies with no exclusion criteria
● studies examining incidence rates of both blood group incompatibility and G6PD deficiency
levels
● incidence rates of infections and idiopathic jaundice were also analysed if reported.
Finally, we examined the use of the additional tests such as tests for conjugated and
unconjugated hyperbilirubinaemia, medical co-morbidity, prolonged jaundice and the
bilirubin/albumin (B/A) ratio. The calculation of the B/A ratio has long been suggested as a
‘proxy’ for free bilirubin, because if albumin levels are low then there is more unbound

87