URICA-II; a Longitudinal Study to Analyse the Correlation Between Urinary Carbonic Anhydrase (CAI), a Marker of Haemolysis, and Bilirubin
In newborns, intravascular hemolysis (the breakdown of red blood cells inside the blood vessels) can range from mild, as part of the physiological (normal) turnover of red blood cells, to severe in cases such as jaundice (an increase in bilirubin levels) Early biomarkers of haemolysis would improve neonatology (newborn) practice by identifying at-risk patients, particularly if the assay is simple, rapid, non-invasive and quantitative. Our now-completed URICA trial on full-term male babies showed that the small cytoplasmic protein carbonic anhydrase I (CAI), found abundantly in red blood cells, was detected in 17 out of 26 urine samples collected once per recruited baby at the neonatology ward. CAI-positive samples were obtained from babies with levels of bilirubin that were rapidly rising or peaking above the threshold for phototherapy. CAI-negative urine was obtained when either bilirubin did not reach phototherapy (a light treatment used for excessive jaudice) threshold, or after it had recovered from its peak. On four occasions, the cause of CAI-positive urine was undetermined. Since CAI is normally absent from urine, a positive signal is indicative of intravascular hemolysis and confirms that CAI crossed the glomerular barrier (a barrier within the kidneys that filters large molecules). However, the quantitative power of urinary CAI to predict and estimate an impending haemolytic crisis requires a new longitudinal study, which is the objective of the URICA-II trial. The URICA-II trial would recruit 30 full term newborn infants delivered at the Evelina London Children's Hospital. The babies recruited would be expected to stay in the hospital for at least 5 days due to treatment for jaundice, infection or some other condition. Participants will have daily non-invasive (bag) urine samples collected and daily transcutaneous (skin) bilirubin levels recorded upto 10 days. The study will last upto 2 years.
• Greater than 36 weeks gestation infants admitted to the neonatal unit and expected to be an in-patient for at least 5 days