More and more tests are performed on plasma. Record-keeping has increased dramatically. There has been an increase in the number of recalls. A large variety of events may raise questions about a product. Or, a laboratory test on one donor may have been recorded incorrectly, and the mistake discovered after the product is made.
Some issues are highly technical.
Often products that actually are safe are discarded or quarantined, resulting in frustrating shortages and wasted resources. The low frequency of such individuals and the efficacy of current viral inactivation methods has prevented transmission of HIV, hepatitis B and C in modern concentrates. Inadvertent, undiscovered microbial or other contamination during manufacture of either plasma-derived or recombinant concentrates is unlikely but possible. There is no such thing as a guaranteed perfectly safe concentrate. Plasma collectors and fractionators continually improve testing, record-keeping and all other aspects of good manufacturing practice while trying to keep an adequate supply of concentrate on the market.