Retrospective assessment of prenatal alcohol exposure by detection of phosphatidylethanol in stored dried blood spot cards: An objective method for determining prevalence rates of alcohol consumption during pregnancy

Abstract

Aims: To analyze the efficacy of screening banked newborn dried blood spots (DBS) for detection of phosphatidylethanol (PEth), a direct alcohol biomarker, with the purpose of performing a retrospective assessment of statewide prevalence rates of alcohol consumption in late pregnancy that results in risky prenatal alcohol exposure.Design: Residual DBS samples collected for newborn screening and stored by a state department of public health were examined for concentrations of PEth. The prevalence of prenatal alcohol exposure, as determined by this direct alcohol biomarker, was compared to prevalence rates of alcohol consumption during pregnancy that have been derived from multiple state-based and national studies using maternal self-report surveys.Setting: DBS cards representative of the general newborn population were collected from multiple hospitals across a single midwestern state. Participants:Two hundred fifty anonymous newborn DBS collected for routine metabolic screening in a midwestern state were requested through the Virtual Repository of Dried Blood Spots. Measures:Concentrations of PEth, a highly specific biomarker of alcohol consumption, were analyzed using a liquid chromatography-tandem mass spectrometry method validated by our laboratory. Findings:Of 250 DBS examined, 4% were positive for PEth (PEth ≥ 8 ng/ml) which is indicative of exposure to maternal alcohol consumption during the last month of pregnancy.Conclusions: Detection of PEth from newborn DBS cards can identify prenatal alcohol exposure and also be used for retrospective surveillance of alcohol consumption during the last three to four weeks of pregnancy, using specimens that are collected for routine metabolic screening and stored by many state health departments.

Prevalence of alcohol use in late pregnancy

“…27,28 Some researchers have reported values above the limit of detection (LOD, ≥2 ng/ml) to indicate positive PAE, 27 while others have proposed that future research should ascertain if PETH concentration in DBS samples between 2 and 8 ng/ml should be considered as light alcohol use and ≥8 ng/ml should be considered moderate to heavy alcohol use in pregnancy. 12 For this study we used the cutoff of ≥8 ng/ml based on several previous reports suggesting the limit of quantification (LOQ) indicated any alcohol use. 12,14,16,22,23 A previous validation article notes that this cutoff has 100% specificity and lower but comparable sensitivity to other methodologies to detect moderate chronic or intermittent binge drinking patterns during pregnancy.…”

“…PETH is a long-term biomarker of alcohol ingestion, which can be detected and measured in the DBS, 13 and indicates PAE in the month prior to birth. 12 The DBS specimens were analyzed at USDTL using previously published methods. 22 The limit of detection (LOD) was 2 ng/ml; the limit of quantitation (LOQ) was 8 ng/ml and the assay was linear up to 200 ng/ml.…”

“…For this study, given no amount of alcohol has been established as safe during pregnancy, a positive PETH result was defined as the LOQ of a reading of ≥ 8 ng/ml or 0.08 g in 100 ml. The cutoff was based on the works of Jones et al 22 and Baldwin et al 12 on alcohol detection in the DBS by USDTL. Other researchers have also used PETH cutoff at ≥ 8 ng/ml to indicate a positive and moderate to heavy alcohol use in the last month of pregnancy.…”

“…10 Currently, there are no standard laboratory tests that can definitively detect alcohol use in pregnancy due to its rapid metabolism; thus, testing maternal blood, breath, or urine is only useful for alcohol exposure within the previous 24 h. 11 Phosphatidylethanol (PETH) is a direct metabolite formed from alcohol (ethanol) consumption, manifesting as a phospholipid incorporated into the membranes of red blood cells. 12 PETH from dried blood spots (DBS) has been shown to be a valuable test with a high degree of sensitivity for assessing PAE at birth. [12][13][14][15] PETH has a long half-life of 3-5 days and a positive PETH value is indicative of late pregnancy PAE (2-4 weeks).…”

“…[12][13][14][15] PETH has a long half-life of 3-5 days and a positive PETH value is indicative of late pregnancy PAE (2-4 weeks). [12][13][14][15][16] Although there is a positive linear correlation between degree of alcohol consumption and PETH concentrations, there have been no established PETH cutoffs that differentiate various levels of alcohol consumption (low vs. moderate vs. heavy) during pregnancy. 17 In 2009, an umbilical cord tissue study was conducted at eight hospitals in WV to estimate the rate of intrauterine substance exposure (IUSE) in the state.…”