Effect of β propiolactone viral inactivation on α1 antitrypsin values
- Immunology Department, Combined Laboratories, Level 7, Derriford Hospital, Plymouth PL6 8DH, Devon, UK
- Correspondence to: Dr S Katona, Department of Immunology, Level 7, Combined Laboratory, Derriford Hospital, Plymouth PL6 8DH, Devon, UK; katonas{at}doctors.org.uk
- Accepted 2 May 2002
Abstract
Aims: α1 Antitrypsin was undetectable in several patient samples treated with 0.5% β propiolactone, which was used as a virucidal agent. This study was designed to confirm β propiolactone as the cause and determine why it might have such an effect.
Methods: Volumes of 0, 5, 10, and 20 μl of β propiolactone were added to 2 ml aliquots of serum to make final concentrations of 0%, 0.25%, 0.5%, and 1% of β propiolactone. α1 Antitrypsin concentrations and the pH were measured at different time intervals. The effects of adding buffer before the addition of β propiolactone, NaOH after β propiolactone, and 6M HCl instead of β propiolactone were also measured.
Results: The addition of β propiolactone to a volunteer’s serum showed a fall in both α1 antitrypsin values and pH with increasing time and concentration of β propiolactone. This effect was also seen when adding HCl, but was partially prevented by buffering the serum or adding NaOH.
Conclusions: These results suggest that it is the acidity of the degradation products of β propiolactone that is responsible for the fall in α1 antitrypsin values. This fall in α1 antitrypsin values was dependent on the concentration of β propiolactone used and the length of time before the test was performed. The effect of β propiolactone on laboratory tests should be re-evaluated, with attention being paid to sample pH, storage time, and storage temperature.
