Transfusion Experts Argue for Better Data to Estimate Blood Needs

Current estimates of needed blood donations to meet a country’s blood needs are outdated and may be flawed from the start, according to a team of experts from the blood community who contributed a “Viewpoint” article published in The Lancet. Better estimates that account for country-based are needed to better understand and meet blood needs globally.

Traditionally, a whole blood donation rate of ten donations per 1,000 population has been considered the minimum necessary to meet a country’s blood needs. However, the article’s authors—several of whom are AABB members—argue that this estimate, derived from a 1971 World Health Organization (WHO) report, lacks references or supporting data, suggesting it may be faulty.

Regardless of whether this estimate was ever accurate, “the collective health care system infrastructure, the scope of medical procedures and practices, knowledge pertaining to evidence-based hemoglobin thresholds for blood transfusion, the methods for storing and conserving blood products, and the availability of blood alternatives have changed,” the experts wrote.

More accurate measures of blood needs are necessary to allow for better health service provision and planning, particularly in low-income and lower-middle-income countries. Better modelling of blood needs should account for geographical variability in disease burden, health care infrastructure and transfusion practices. Unfortunately, this data is lacking in many countries.

The authors believe that greater effort is needed to improve data collection, particularly in low- and middle-income countries. Such efforts should include epidemiological data on epidemiology of the most frequent medical conditions and procedures requiring blood transfusion in a particular geographical area. The authors noted that sickle cell disease and malaria, for example, are “highly prevalent in sub-Saharan Africa and represent major components of regional blood use.” Whereas, these conditions are less relevant in other regions.

In addition, better estimates of blood needs should also account for the complexity of the medical procedures commonly performed in each region, given that blood use varies by procedure type, anatomical location, the use of open versus less invasive interventions and the extent of comorbidity. Better modelling should also account for changing blood needs over time. Assuming steady-state conditions is unrealistic in many settings where disease incidence varies with season (e.g., malaria and dengue).

The authors concluded by arguing that propagation of the estimate of ten donations per 1,000 population to assess a country’s blood needs “should be discouraged as it is potentially misleading, uninformative and assumes that a single figure will cover all countries’ needs.” Instead, they call for a “transition to individualized, evidence-based indices could facilitate strategic investment in the global blood supply.”