Mark H Yazer, Emilie A Jochumsen
These results support titer testing of all donations because seasonal variation in the donor high titer rate was not demonstrated and many donors who initially tested above the 100 titer threshold subsequently tested below it, though the magnitude of titer change could not be determined with the single-dilution method used.
OBJECTIVE: This study evaluated the proportion of high anti-A and/or anti-B titer blood donors at a large blood collector over >3 years.
METHODS: Donors of products that could be used in an ABO-plasma incompatible manner were titer tested. Low titer was defined as <100. The study period was January 27, 2020 through May 13, 2023.
RESULTS: A total of 11,145 unique donors made 30,035 titer tested donations. There were 843/11,145 (7.6%) donors who made at least one high titer donation. There were 106/167 (63.5%) donors who made a high titer donation on their first donation and subsequently made a low titer donation after a median (95% CI) of 116.5 days (89-160 days). The high titer rate for all donors varied from a low of ~2.8% in Q3 2020 to a high of ~5.9% in Q1 2022, with no clear seasonal periodicity among high titer donors. The majority of donors who made at least one high titer donation were group O (589/843, 69.9%). There was a slight female predominance among high titer donors along with a greater representation of younger donors compared to those who only made low titer donations.
CONCLUSIONS: These results support titer testing of all donations because seasonal variation in the donor high titer rate was not demonstrated and many donors who initially tested above the 100 titer threshold subsequently tested below it, though the magnitude of titer change could not be determined with the single-dilution method used.