Protocol to Measure Hair Cortisol in Low Mass Samples From Very Preterm Infants.
Marliese Dion Nist, Brent A Sullenbarger, Tondi M Harrison and 1 others
PMID 32287079WHAT IT FOUND
A new hair cortisol protocol detected cortisol in 25 of 29 very low mass hair samples from very preterm infants, including samples as small as 0.4 mg.
It is a research method, not a confirmed clinical stress test.
Key findings
01The modified protocol detected cortisol in 25 of 29 hair samples, or 86%.
02Cortisol was detectable in hair samples weighing as little as 0.4 mg, with a mean level of 23.74 pg/mg hair (SD 26.38 pg/mg hair).
03In exploratory analyses, few demographic or clinical variables were associated with hair cortisol; only postnatal caffeine exposure and prenatal maternal antibiotic exposure were significant.
STILL TO COME
How it was doneWhat they foundWhat it means for RNs
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What it does not show
Only 29 hair samples were analyzed. Mothers of 36 of 73 infants consented to hair collection, and hair could not be collected from 7 infants because there was too little hair. The infants were a selected subset of a larger study, born at 28 to 31 weeks postmenstrual age, admitted to four Midwest NICUs, and excluded for sepsis, congenital anomalies with known neurodevelopment effects, chorioamnionitis, neonatal abstinence syndrome, small-for-gestational-age birth, neurologic abnormality, or maternal oligohydramnios. Hair was collected at about 35 weeks postmenstrual age, and the authors say hair cortisol should only be compared when collected at the same approximate age. The method’s accuracy and precision were not confirmed, and there are no published normal reference ranges for hair cortisol in preterm infants. The added cortisol spike can introduce error because recovery of the spike may differ; the study averaged duplicate wells but did not test incremental spike levels. The associations with caffeine and antibiotics were exploratory, not a test of whether the protocol predicts clinical outcomes.
Declared interests
The authors declared no conflict of interest. The paper’s publication types list NIH extramural and non-U.S. government research support.
The easy way to misread this
Do not read the 86% detection rate as proof that hair cortisol is a confirmed clinical measure of stress in preterm infants. The protocol’s accuracy and precision were not confirmed, there are no preterm infant reference ranges, and the sample was small.