New Delhi, July 26: Medical researchers have proposed a novel blood test to detect life-threatening sepsis in newborns that they say could provide results within two hours in contrast to the standard diagnosis that takes at least two days.
A preliminary study by a team of researchers in Chandigarh, Jaipur and New Delhi has indicated that changes in a class of white blood cells and levels of a blood protein may be combined for the new test.
Haematologist Manorama Bhargava and her colleagues say the test they have proposed, if validated through a bigger study, could help doctors provide timely treatment and avoid unnecessary use of antibiotics to fight suspected sepsis (severe blood infection).
Paediatricians and public health experts say sepsis accounts for one in three of India’s estimated 900,000 deaths each year among neonates, or children less than a month old. Most cases of sepsis, they say, is caused by common bacteria that can quickly overwhelm the immune system and invade the lungs and other organs of the newborn.
Doctors typically suspect sepsis when a newborn has fever or quick spikes and dips in body temperature, breathing trouble, reduced movements and poor feeding, among other symptoms. While doctors do measure blood cell counts and the ratios of certain white blood cells to help diagnosis, paediatricians say the “gold standard” diagnosis is through blood culture that takes anywhere from 48 to 72 hours.
“The complete blood count picture and white blood cell ratios have limited use in the diagnosis of neonatal sepsis,” said Bhargava, a senior consultant haematologist at the Sir Ganga Ram Hospital, New Delhi.
“Their ability to correctly identify positive cases and rule out negative cases is unacceptably low.”
In their study, Bhargava and her collaborators have shown that the volume of a class of white blood cells called neutrophils combined with the levels of a protein called C-Reactive Protein appears to be a reliable predictor of neonatal sepsis. They have published their study in the International Journal of Laboratory Haematology.
“The neutrophils are the first line of defence against infections and CRP is an indicator of inflammation,” said Satish Saluja, a senior neonatologist and research collaborator.
“In response to sepsis, the body releases neutrophils and the younger neutrophils have relatively larger volume than older ones that are consumed by the infection,” Saluja said.
The researchers examined average neutrophil volumes and CRP levels in 94 newborns with suspected sepsis and 36 other newborns who had blood tests for other reasons and were used as “healthy controls” in the study.
The doctors found that the combination of these two parameters was a reliable predictor of sepsis, which was confirmed through blood culture tests in only 35 babies with suspected sepsis.
The researchers say the combined test for neutrophil volume and CRP will take only two hours and could guide paediatricians in choosing the line of treatment with greater confidence while they wait for the blood culture results to come in.
“The use of neutrophil volume as an indicator of sepsis is something new,” said Shailesh Patil, a paediatrician at the Seven Hills Hospital, Mumbai, who was not connected with the study.
“We’re already using CRP to help in diagnosis but because it is not so reliable, the paediatric community has been looking for new predictors.”
Bhargava, Saluja and their collaborators at the Postgraduate Institute of Medical Education and Research, Chandigarh, and Banasthali Vidyapeeth, Jaipur, have labelled the average neutrophil volume and CRP as a potential tool to diagnosis neonatal sepsis.
Saluja said: “We’re hoping others will validate this through studies on larger samples of children.”