The only correct answer to that question is “It may be.” All older blood of that vintage appears to test Rh neg. The older the blood, the more likely the test will report a negative Rh factor. Perhaps something in the Rh positive factor dissipates with time,
Thank you. That’s interesting. I wonder if anyone has studied that dissipation rate. I remember reading that the blood was Rh neg. I hadn’t heard before that that might be due to the age of the blood. Is there blood from the Medieval ages that doesn’t test Rh neg?