Has anyone seen the antibody screen become completely negative after a patient was transfused with plasma and platelets. We saw a patient the other day in the ED with positive screen and Anti-FYA. Received uncrossmatched blood and plasma and was transferred to another facility. Later they performed a type and screen on the patient and it was completely negative. Both our facilities use solid phase testing. Wrong blood in tube was ruled out. Thank You

We did a Plasma Exchange recently on a patient 5 days in a row with approximately 10-12 units of FFP each time.

On day 3, the band expired and we retested the new sample to find the previous antibody had disappeared.

It's a dilutional effect where the titer is dropped below detectable levels.

I agree Darin, it is almost certainly a dilutional effect, BUT, it could also be the effect of a soluble antigen (obviously not within the Duffy Blood Group System). If the antibody had a specificity within, for example, the Lewis Blood Group System, or the Chido/Rodgers Blood Group System, the antigen in the plasma could well adsorb out the circulating antibody. That having been said, this explanation is FAR less likely than your suggestion of the dilutional effect.

Thanks for all your input

My question would be - how strong was the pre-transfusion reactivity? If it was only 1-2+ in SP / and the patient isn't a "larger" person, I personally would suspect that the antibody titer was diluted to such a degree that SP did not pick it up anymore....... (but I REALLY don't like SP.....it's just too wishy-washy.....JMHO)

How many units of uncrossmatched blood did they receive? How active were they bleeding? How much later did the other hospital preform their own T&S? Inquiring minds want to know!!! 😉

Several units of blood and plasma, in fact an MTP was called. Patient was actively bleeding.

Sounds like a dilutional effect. How big is the patient and how much plasma/platelets did the patient receive during the time frame between blood draws?

I have seen this with massively transfused patients and with plasma pheresis patients and with patients who have received multiple products over a few days.

Does anyone know of any research done on this topic, or any Journal articles?

Also, were any of the transfused units antigen positive? This is the quickest way to get a negative indirect antiglobulin test ;).

2 hours ago, Neil Blumberg said:

Also, were any of the transfused units antigen positive? This is the quickest way to get a negative indirect antiglobulin test ;).

AGREED - and killing the patient in some circumstances!!!!!!!!!!!!!!!!!!

Just wanted to follow up on this very interesting case. This patient was seen by our facility again beginning of July, anti-FYA still showing. A week later she was seen at the other facility in our system and her antibody screen was negative there. We both use solid phase. They have Neo by Werfen/Immucor. We have Echo by werfen/immucor. It is really perplexing. Has anyone seen anything like this? I mean both instruments are similar, I thought only difference was size.

18 minutes ago, bblover said:

Just wanted to follow up on this very interesting case. This patient was seen by our facility again beginning of July, anti-FYA still showing. A week later she was seen at the other facility in our system and her antibody screen was negative there. We both use solid phase. They have Neo by Werfen/Immucor. We have Echo by werfen/immucor. It is really perplexing. Has anyone seen anything like this? I mean both instruments are similar, I thought only difference was size.

Just an idea ... even two side by side ECHO analyzers could produce these varied results with low titer antibodies. How hard they are set to shake, actual wash volumes, condition of lights and cameras. etc.

It is showing pretty strongly (3-4+) on Echo.

In that case, I'd be having service come out for that NEO.

Is there any risk of contamination of the screening red blood cells (stroma) with proteolytic enzymes (e.g., papain, ficin) on these systems ? From a diluent used for other assays (some antigen typing tests or antibody screening with enzyme treated cells)?