Donor blood lead levels and transfusion safety in a vulnerable population

Measurement of lead, mercury, and cadmium in blood donors in Canada

BACKGROUND

Fetal and neonatal exposure to lead is associated with irreversible adverse effects on neural development. There is no reliable threshold for lead effect, so limiting exposure is recommended. A significant correlation has been reported between post-transfusion blood lead level (BLL) in infants and lead levels in transfused RBC units. We measured levels of lead, mercury, and cadmium, in Canadian donor blood to investigate if concerning levels for neonatal transfusion exist.

STUDY DESIGN AND METHODS

Whole blood samples from blood donors (n = 2529) were shipped cold within 7 days of donation. All permanent blood donation clinics across Canada were sampled. Twelve of these permanent clinics and 8 mobile clinics with a greater potential for having higher lead or mercury levels were oversampled. Heavy metals were measured by inductively coupled plasma mass spectrometry.

RESULTS

Of all donations, 2.2% (lead) and 0.4% (mercury) had levels higher than the recommended thresholds for safe neonatal transfusion. BLLs were higher in males but there was no significant difference in the blood mercury levels of males versus females. Cadmium levels were higher in females. There was a positive correlation between donor age and levels of heavy metals, with lead having the strongest correlation (r = 0.47, p < .0001). Three clinics in close proximity to two lead-producing mines were among the clinics with the highest BLLs. Significantly higher blood mercury levels were observed in coastal clinics.

CONCLUSION

Our data on donor blood heavy metal levels supports considering blood transfusion as an exposure source to heavy metals and encourages informed selection of blood units for transfusion to vulnerable groups.

Blood donation and heavy metal poisoning in developing nations: Any link?

Long term health effects of heavy metal exposure from both occupational and environmental settings involve multi-organ toxicities including but not limited to disturbances of neurological, cognitive, and metabolic processes, immune system dysregulation, carcinogenesis and sometimes permanent disabilities. Humans are exposed to toxic metals through various sources and routes of entry. The risk of heavy metal poisoning from donor blood has been the subject of many scientific investigations. In this review we highlight how the access to a safe and adequate blood transfusion with minimal risk of toxic metals to recipients is a public health challenge, especially in developing nations. For quality assurance purposes, blood donors are screened for various blood-borne pathogens, but screening for toxic metal levels is not routine. Evidence from scientific studies used in this review lends credence to the risk of heavy metal poisoning from donors with high blood concentrations of these heavy metals. The risk of toxicity is exceptionally high in vulnerable populations such as neonates and preterm infants, as well as in pregnant women and other individuals with conditions requiring multiple blood transfusions. This is worse in developing countries where some members of the population engage in illegal refining and artisanal mining activities. In order to reduce toxic metal exposure in vulnerable populations, blood meant for transfusion in vulnerable subjects, e.g. children, should be routinely screened for heavy metal concentrations. Patients receiving multiple blood transfusions should also be monitored for iron overload and its attendant toxicities.

Lead: a hidden "untested" risk in neonatal blood transfusion

BACKGROUND

Neonates may be exposed to lead (Pb) through blood transfusions from donors. Pb exposure has neurological, cardiovascular, renal, and other adverse effects. The study aimed to (i) determine the blood lead levels (BLLs) in different blood product units (whole blood, packed red blood cells (pRBCs), platelets, and plasma transfused to neonates) and (ii) estimate the proportion of units with high BLLs.

METHODS

Residual blood from blood bank bags that were used for neonatal transfusion were collected: 25 samples from each type of blood product except for whole blood (10 samples). The Pb analysis was performed using the atomic absorption method. The study was conducted at the Suez Canal University Hospital, Egypt.

RESULTS

The mean of BLL in pRBCs, platelets, plasma, and whole blood were 136, 199, 108, and 130 µg/L, respectively; 60% contained Pb above 50 µg/L. The highest BLLs were in platelet units.

CONCLUSIONS

The present study showed for the first time that platelets and plasma in addition to whole blood and pRBCs used for neonatal transfusions are sources of Pb. Re-evaluation of the guidelines is mandatory for the safety of the neonates. Long-term neurodevelopment assessment of neonates exposed to high Pb is warranted.