Diagnostic companies developing antibody tests for COVID-19 report that high prices for the blood of recovered patients are affecting test development. Convalescent blood is critical to developing antibody tests, since accuracy is determined by comparison against control samples. To obtain emergency approval for COVID-19 antibody tests, the FDA requires developers to run tests against at least 30 positive and 75 negative samples. Test developers are also required to include a vial of convalescent plasma in tests sold to laboratories, so researchers have a positive control to compare with each batch.
Depending on the condition and sourcing logistics, the price for "disease-state" blood can vary from a few dollars to several hundred dollars per sample. However, in some cases, diagnostics companies are reporting four-figure prices in some cases for COVID-19 positive samples, according to The Wall Street Journal.
Much of the blood donated to hospitals and nonprofit blood banks is currently being reserved for use in experimental treatments for cases of severe COVID-19, so the diagnostics industry is left to look elsewhere to source materials. Blood brokers, which typically get their supplies by running donation centers or collecting leftover blood from laboratory tests or clinical sites, are one example.
Even blood brokers are facing hurdles collecting their supplies. As the number of cases fall over time, the supply dries up. In addition, only around a third of donated blood has high enough antibody levels to be used as a positive control in testing.
Some diagnostic companies are attempting to cut out the middleman by soliciting their own donations. Massachusetts-based Kephera Diagnostics began directly asking patients recovered from COVID-19 for free donations of blood taken from a finger prick. The company is currently using a mix of donated finger-prick blood and purchased plasma to develop its antibody test.