Free plasma haemoglobin Assay and H indices & neonatal bilirubin assay
Research type
Research Study
Full title
Evaluation of Free Plasma Haemoglobin assay kit, comparison with autoanalyser 'H' indices in surplus neonatal serum and investigation of possible solutions for improving neonatal bilirubin assay.
IRAS ID
164602
Contact name
Tim Reynolds
Contact email
Sponsor organisation
Queen's Hospital
Duration of Study in the UK
1 years, 2 months, 31 days
Research summary
Paediatric blood samples are often sent to the laboratory for analysis of bilirubin. In excess, this can be very dangerous, leading to brain damage (kernicterus). Consequently, in neonates that appear jaundiced bilirubin is monitored closely to determine which babies need phototherapy (blue fluorescent light therapy) to photodegrade bilirubin. Phototherapy extends the time the baby is kept in hospital and therefore it is important to only treat those who need it, rather than toplay safe and treat all babies that appear a little bit yellow.
Blood samples are frequently collected from neonates by heel prick. To get enough blood for analysis it is often necessary to squeeze the baby’s heel hard which can result in the blood sample being haemolysed. Modern analysers include a set of indices [L(ipaemia), I(cterus – bilirubin/ jaundice), H(aemolysis)]. If the sample exceeds thresholds defined for each index then certain tests are automatically flagged as unreliable. For paediatric samples, the critical flag is the H index which frequently blocks reporting of the bilirubin result because the absorbance wavelength of the red colour of haemoglobin is close to the peak wavelength of the azobilirubin reaction product in the Jendrassik-Grof bilirubin assay.
The problem of blocked reporting of bilirubin in neonates has become greater in recent years because previously H indices were not measured and rejection of a bilirubin request was based on the laboratory scientists eye [if the sample looked too red then the test would be rejected]. Now H indices are measured on all it has become clear that far more samples should have been rejected in the past. This causes a problem for paediatricians because it is difficult to get samples from neonates (and especially small for dates neonates / premature babies, which are more likely to have bilirubin problems due to the immaturity of their liver enzymes).
An alternative method that can get around this problem therefore needs to be identified.
REC name
Yorkshire & The Humber - South Yorkshire Research Ethics Committee
REC reference
14/YH/1238
Date of REC Opinion
3 Dec 2014
REC opinion
Further Information Favourable Opinion