Science Buddies: "Ask an Expert"

How Are Antibodies Used for Blood Typing?
I have a student who purchased your kit and performed the experiment with the blood samples (provided in kit) at different temperatures.He and I did several trials with the blood samples and the antigens at approximately 10, 21, 37 and 73 degrees Celsius. His objective was to determine if temperature affected blood typing results. I want to make sure that I understand the kit. There were four unknown synthetic blood samples provided in the kit. He lowered and raised the temperature of his components with ice, and a water bath. We observed the "clumping" reaction with Anti A, Anti B, and Anti Rh for each sample to determine the blood type.

My understanding is that temperature should not affect the results of the blood typing but his results had some inconsistencies and showed some different blood types.

We have looked everywhere and found that temperature can affect the equilibrium constant in agglutination but nothing on actually interfering and changing the determination of the blood type.

He has worked very hard and I want to help him. Can somebody please help me guide this student?

From what I understand the clumping means the antigen exists in the sample. Is it possible that all 4 samples happened to be AB+ ?

No. All of the blood samples said they were different (sold as 4 unknowns). Yes, the "clumping does mean the antigens is present. Alternate Hypothesis: Blood and antigen temperatures over 70°C will cause a change in agglutination which will alter the blood type

In generalm anti-A and anti-B antibodies are IgM antibodies that tend to clump better at room temperature. Anti-Rh antibodies are usually IgG antiodies that work better at 37oC or a little warmer (but 70oC is pretty warm). If this kit contains some kind of synthetic clumping factors to replace the antibodies, these synthetic components might not behave in a way that would mirror true blood samples.