Unexpected Causes of Contamination in Newborn Immunnoassays Give Positive THC Results

In Recent News, Unexpected Causes of Contamination in Newborn Immunnoassays Give Positive THC Results
By Nancy J Parra, MA, Marketing Communications Manager

A study, published in the June 2012 issue of Clinical Biochemistry, looked into the occurrence of a high rate of positivity for THC in newborn urine and revealed surprising results. External contamination caused by common baby washes used by the hospital for the newborn’s first bath resulted in (unconfirmed) positive THC screens.

According to researchers from the University of North Carolina, Chapel Hill, the amount of baby wash in urine needed to result in an initial positive test was less than 0.1 milliliters. This means that tiny levels of soap left on the baby can trigger an initial positive THC test in the baby’s urine. Researchers believe the substance is not absorbed through the baby’s skin, but washed into the urine from traces left on the skin.

After further inquiry it was discovered that none of the newborn urine specimens had been confirmed by an appropriate GC-MS or LC-MS/MS method but were screen-only results.

Newborn screening for exposure to alcohol and substances of abuse is an important and serious matter. Unconfirmed urine screens can be tainted and, therefore; hold no forensic value.

The study by the University of North Carolina, Chapel Hill concludes: It is important for laboratories and providers to be aware of these potential sources for false positive screening results and to consider confirmation before initiating interventions. Most importantly, we demonstrate the need for active involvement in the total testing process, as sources of error are not confined to the laboratory walls.

Screening for suspected exposure must be confirmed by GC-MS or LC-MS/MS if the healthcare provider intends to use the information to provide important services for the child.

USDTL offers GC-MS and LC-MS/MS assays where all positives are confirmed before the results are reported, saving time and money in the long run, while providing forensic substantiation. For more information contact Client Services at 800-235-2367.