Phosphatidylethanol, mostly referred to as PEth, is a phospholipid biomarker of long-term alcohol consumption. PEth exists naturally in red blood cells, and its formation in the blood is catalysed by phospholipase D (PLD) in the presence of ethanol. PEth accumulates with frequent alcohol consumption and has a half-life in the blood of approximately 4 days (Helander et al., 2019).
PEth quantification is used to identify long-term alcohol consumption in diverse fields including occupational health, family (custody) law, and forensic medicine. Given that PEth analysis may lead to drastic outcomes for the individual being tested, it is critical that the sampling and testing is performed accurately to yield a reliable result.
Capitainer®B Vanadate is developed especially for accurate microsampling and PEth analysis. It outperforms traditional testing methods by eliminating the risk of falsely elevated PEth levels due to post sampling formation and by guaranteeing an accurate blood sampling volume every single time. Moreover, the transition from venous blood sampling to microsampling with finger-prick blood makes it possible to perform alcohol and PEth testing outside of healthcare systems and without expertise in phlebotomy.
Traditional PEth testing may yield unreliable results
Traditionally, PEth is analysed from venous blood draws taken by a trained phlebotomist.
One major problem with traditional testing is that PEth will continue to form in vitro post-sampling if any amount of ethanol is present in the blood at the time of the blood draw.
In vitro PEth formation can make it impossible to distinguish between mild and chronic or binge alcohol consumption. This may make traditional PEth analysis results unreliable.
Capitainer®B Vanadate eliminates the risk of false positive samples
In vitro PEth formation can be prevented by inhibiting PLD activity immediately after blood sampling. Sodium metavanadate (NaVO3) has been shown to be an effective PLD inhibitor, and this is incorporated into our Capitainer®B Vanadate device for accurate and reliable PEth testing.
The Capitainer®B Vanadate device is, like all Capitainer’s products, based on the well-established dried blood spot (DBS) sampling method. Our proprietary technology of incorporating NaVO3 in the DBS paper disc eliminates the risk of PEth formation post-sampling, thus bypassing the false-positive risk associated with other PEth testing methods. Capitainer®B Vanadate has been demonstrated to outperform PEth testing from traditional venous samples (Beck et al., 2021, Schröck et al., 2018).
Conventional DBS makes it difficult to determine sample volume
Conventional DBS is widely used for qualitative or semi-quantitative analyses such as screening for the rare disorder phenylketonuria (PKU) in newborns. While DBS has proven successful in qualitative analyses, PEth analysis relies on the quantification of PEth in a person’s blood at a specific time point. A quantitative analysis requires an exact sample volume.
How big is a blood droplet from a finger prick? This depends on many factors, including the size of the lancet needle using for blood drawing, individual blood circulation, and hand temperature of the person being tested, to name a few.
When the drop of blood is released onto a conventional DBS filter, it is impossible to determine the exact sample volume. A common practice is to sub-punch the filter to produce a disc of known size, which is assumed to harbour a fixed blood volume. Although widely used, this accuracy of this approach is hampered by the hematocrit effect, whereby the haemoglobin level in the blood influences its viscosity, which in turn influences how the blood diffuses through the filter (Denniff & Spooner, 2010). This may lead to sub-punches from different regions yielding completely different PEth readings. The hematocrit effect, which is a well-documented phenomenon, renders conventional DBS unsuitable for accurate PEth analysis.
Accurate sample volume every time with Capitainer®B Vanadate
Capitainer®B Vanadate bypasses the hematocrit effect, and provides a unique solution to PEth testing by ensuring a sample volume of exactly 10µl, every single time.
In our device, the DBS disc is pre-cut prior to blood sampling to perfectly fit the wells of a standard 96-well plate. Since Capitainer® B Vanadate uses the full disc for PEth testing, the hematocrit effect can be disregarded.
Capitainer®B Vanadate – the new gold standard for PEth analysis
Capitainer®B Vanadate is a microsampling device that can be used for both self-sampling and assisted sampling. A blood sample is taken by the device through a finger prick and a droplet of blood is automatically applied to the integrated DBS filter. The user will receive an instant confirmation on the device if the sampling is successful. In other words, no responsibility is put on the end user to decide whether or not the sample volume is correct, since this process is completely automated within the device.
The Capitainer®B Vanadate device is proven to be very user-friendly and does not require the presence of a phlebotomist. By following the instructions for use, self-sampling or assisted sampling is performed efficiently, ensuring an accurate blood sample for analysis.
Since the blood in the disc is dry, it is not considered a biohazard, which means that the sample neither requires refrigerated transportation nor cold storage before analysis. This important feature enables any laboratory to receive samples from a much greater geographical area than would otherwise be possible. Lab automation and protocols for mass spectrometry, which are already up and running in laboratories in Sweden, are available from us upon request.
Read more about the detailed technology of Capitainer®B Vanadate here.
Are you interested in testing Capitainer®B Vanadate? Please contact us here to apply for a free sample.
- Helander, A., Böttcher, M., Dahmen, N., & Beck, O. (2019). Elimination Characteristics of the Alcohol Biomarker Phosphatidylethanol (PEth) in Blood during Alcohol Detoxification. Alcohol and alcoholism (Oxford, Oxfordshire), 54(3), 251–257. https://doi.org/10.1093/alcalc/agz0277
- Beck O, Mellring M, Löwbeer C, Seferaj S, Helander A. Measurement of the alcohol biomarker phosphatidylethanol (PEth) in dried blood spots and venous blood—importance of inhibition of post-sampling formation from ethanol. Anal Bioanal Chem. 2021. 413, 5601–5606. https://doi.org/10.1007/s00216-021-03211-z
- Schröck A, Henzi A, Bütikofer P, König S, Weinmann W. Determination of the formation rate of phosphatidylethanol by phospholipase D (PLD) in blood and test of two selective PLD inhibitors. Alcohol. 2018. 73, 1-7. https://doi.org/10.1016/j.alcohol.2018.03.003
- Denniff P, Spooner N. The effect of hematocrit on assay bias when using DBS samples for the quantitative bioanalysis of drugs. Bioanalysis. 2010. 8, 1385-95. https://doi.org/10.1016/j.alcohol.2018.03.003