Biological Reference Intervals for 17α-Hydroxyprogesterone Immunoreactive Trypsinogen, and Biotinidase in Indian Newborns
Department of Clinical Chemistry, Apollo Diagnostics Global Reference Laboratory, Hyderabad 500037, India
Background
Neonatal deaths in the first week of life account for a large share of under-five mortality, and newborn screening programmes exist to move a subset of those outcomes from “too late” to “treatable”. Those programmes are only as good as their decision limits.
Objective
To establish clear biological reference intervals for three routinely screened analytes — 17α-hydroxyprogesterone (17-OHP), immunoreactive trypsinogen (IRT) and biotinidase — in the Indian newborn population, and to examine how their distributions behave across body weight and gestational age.
Approach
Statistical analysis of up to 3,200 dried blood spot (DBS) samples from Indian newborns, with correlation analysis applied to fix the relationships among the three screening parameters.
Reported contribution
The study reports the distribution and comparison of key cut-offs for these biomarkers with respect to body weight and gestational age in the Indian newborn population “for the first time”, and states that the data provide information relevant to new cut-off values in newborn screening programmes.
Reading it correctly
A reference interval is not a screening cut-off. The interval describes where measurements sit in a defined population; a cut-off is an operational decision limit set from that distribution together with assay performance, the sensitivity and specificity a programme targets, and the recall rate it can absorb. This paper supplies the population data that the second decision depends on.