Long-term follow-up testing of red cell alloantibodies.

BACKGROUND

In previous studies, 29 to 34 percent of potentially hemolytic red cell antibodies were not detected after short-term follow-up.

STUDY DESIGN AND METHODS

To examine long-term detection, records were reviewed for 44 consecutive patients who were tested more than 5 years after their potentially hemolytic red cell antibodies were first identified in this hospital.

RESULTS

After 5 to 10 years, 14 (39%) of 36 Rh, Kell, and Duffy system antibodies were not detected on at least one occasion. Twenty-two other such antibodies were sought again after more than 10 years; 10 (45%) were not detected. When restimulation by pregnancy was excluded, these rates were 42 and 48 percent, respectively.

CONCLUSION

Clinically significant red cell antibody formation is probably more common than previously realized, because nearly half of these antibodies are undetected after long-term follow-up.