A subscribing transfusion service physician from Florida asks about antibody titers during hemodialysis. He states,

"Our patient is a 52 yr old woman with numerous medical problems who received transfusions in the mid '70s when she was successfully treated for Hodgkin Disease. On 7/9, she had a positive antibody screen 2+ (by gel) at one of our community hospitals, and anti-E was identified . She was not transfused, but was transferred to our main facility and started on continuous veno-venous hemodialysis. On 7/12, the antibody screen (by gel) was completely negative! After getting the same result on a new sample (thinking it might have been mislabeled), we retrieved samples from hematology from the intervening days and were able to detect the antibody, but it was very weak. She received a lot of fluid for resuscitation and to try to re-establish urine in the interim, but no plasma."

He doubts this is dilutional - although her protein dropped from 6.2g to 5.0g, most of this is from albumin which went from 3.1g to 2.3g. He states that the nephrologist thinks immunoglobulins are too large to pass through the filter, and is wondering if there might be some type of adsorption phenomena going on. Have others seen marked changes in antibody titers during veno-venous hemodialysis?

The following comments have been received.

ADDENDA Aug. 7, 2006

1. Sheryl A. Kochman, Chief, Devices Review Branch at CBER/OBRR/DBA (attribution used with permission) wonders if the apparent decrease in antibody strength under discussion is actually related to the test method that was employed. She comments that the inquiring colleague states that the anti-E was detected at a community hospital using the Gel method but was negative by the Gel method at their facility. A key point might be what kind of Reagent Red Blood Cells (RRBC) were being used. It is recognized that 3% RRBC diluted to 0.8% by the user on the day of use tend to react better with some specificities than 0.8% RRBC purchased from the manufacturer. Anti-E is one of the antibodies that has been repeatedly missed using purchased 0.8% RRBC.

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Ira A. Shulman, MD
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W. Tait Stevens, MD
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