Our June Quick Question asked, “Most laboratories perform a FVIII activity assay before starting a Bethesda titer for FVIII inhibitor. At what FVIII activity level do you cancel the order for the titer?
a. 20% activity: 6 respondents, 35%
b. 30% activity: 3 respondents, 18%
c. 40% activity: 1 respondent, 6%
d. 50% activity: 6 respondents, 35%
e. We do the titer anyway: 1 respondent, 6%
This is another area where the coagulation laboratory could profit from developing a consensus. Perhaps we will hear something at the ISTH meeting in Boston July 11-15 to illuminate this question. Geo.