Researchers at the Centers for Disease Control and Prevention (CDC) in the US have developed a new test that could ensure newborns with homocystinuria (HCU) receive essential treatment.

HCU impedes the ability of an infant to metabolise the amino acid methionine, a component of several proteins, including those found in breast milk.

The test measures the rise in levels of homocysteine, which almost always rise within the first few days of birth in infants with HCU. Furthermore, homocysteine levels usually rise before methionine levels.

In the study, which was published in the American Association for Clinical Chemistry’s (AACC) Clinical Chemistry journal, the researchers’ team used the new test on residual newborn screening specimens obtained from infants who had received diagnoses.

The samples included 50 from HCU-negative infants receiving total parenteral nutrition (TPN), two from HCU-positive patients, and 100 from healthy patients.

The new test distinguished between the healthy and HCU-positive samples and accurately classed the TPN samples as HCU-negative.

Centers for Disease Control and Prevention researcher Konstantinos Petritis said: “Here we present the only flow injection analysis–tandem mass spectrometry first-tier newborn screening method that directly quantifies total homocysteine from dried blood spots.

“The ability to screen total homocysteine during first-tier newborn screening is a significant step toward reducing HCU false-negative rates, which will enable early identification and intervention to reduce HCU-associated morbidity and mortality.”

HCU is a congenital disease that causes serious complications if it is not treated early. The complications range from eye and skeletal issues to vascular abnormalities and intellectual disabilities.