Plasticizer in the plastic bag used to collect and hold the blood leaches into the blood. The plasticizer most commonly used for blood bags is di-(2ethylhexyl)phthalate (DEHP). Metabolites of the plasticizer are excreted in the urine.
Metabolites of DEHP:
(1) MEHP: mono-(2-ethylhexyl)phthalate
(2) MEHHP: mono-(2-ethyl-5-hydroxyhexyl)phthalate
(3) MEOHP: mon-(2-ethyl-5-oxyhexyl)phthalate
The plasticizer is not absorbed after ingestion, so there should be no false positives after drinking from plastic containers or using plastic utensils.
Interpretation:
• A low concentration of DEHP metabolites may be found in people who have not been transfused.
• The presence of elevated levels of plasticizer metabolites in the urine may be an indicator of a recent blood transfusion. An investigation is needed to determine if a blood transfusion is appropriate or an unlawful attempt at doping.
Limitations:
• False positives can occur following intravenous administration of fluids from plastic bags.
• False negatives can occur if a bag is used that has a different plasticizer.
• The plasticizer is cleared in a few days. Waiting a few days would minimize detection but also would reduce the benefit of blood doping.
Additional considerations:
(1) The athlete will show signs of recent venipuncture in a large vein.
(2) Long-term storage of the blood prior to transfusion may be detrimental to the athlete due to release of cytokines and other factors.
(3) Many urine cup are made of plastic. Plasticizer could leach into the urine with time but there would not be any metabolites.
