fbircher said:
meb:
Thanks for the feedback. Now I understand why the overall likelihood of an antigen match differs from the simple ratio of possible combinations. You sound as if you have some expertise in the area of blood analysis/genetics. Based on your understanding of the approach this test uses to flag foreign blood cells, can you envision a way for one test subject to have two different antigen combinations in a statistically significant number of blood cells, other than transfusion? Setting aside the possibility of chimeras and accidental contamination in the lab, can you envision any other scenario that could account for this? It seems to me that the crux of Hamilton's defense will hinge on his ability to explain how he has different antigen combinations present in his blood cells, without having recieved a blood transfusion. Or perhaps he will argue that the test falsely identified differening antigen combinations, when in fact they we're all the same.
Anyone who has ever had a bone marrow transplant would forever test positive (unless the donor came from a twin or was similar in antigen makeup). Sometimes when a blood transfusion is given, bone marrow cells are in the transfused blood- if those set in the recipient’s marrow, those transfused marrow cells will forever become a part of the recipient’s rbc population distribution.
Many types of cancer will throw the antigen testing off. An autoimmune disorder affecting the blood could lead the test reading false positive.
Anemic conditions could also throw the test off (although that would clearly remove him from world class competitive performance).
Some genetic and congenitcal conditions result in a mosaic-ing of phenotypic expression from the genetically expected phenotype. Some cell groups expressing the dominant gene others expressing the recessive. Well known forms of this includes someone with one blue eye and one brown eye or blond hair on part of the scalp and brown or red elsewhere.
Keep in mind since the test is looking for mixed populations, a false low read on an expected positive antigen is a positive test failure result for this transfusion test.
Amongst the blood antigens, heterozygous individuals sometimes produce less than a 100% full population distribution of a couple of the test antigens.
A couple of the antigens have several antigen binding sites so expected 100% populations read inconsistent from test to test making it hard to accurately test a phenotypically positive recipient receiving blood from a phenotypically negative individual.
Similar proteins might bind with the sites blocking the dyed antibodies from binding to the rbc giving a low read
Similar polysited proteins might complex up and bind on one site with a rbc and link a dyed marker giving an unexpected high antigen read.
Nutritional deficiencies might result in undersynthesis of an expected 100% population for an expected antigen or an exhausted athlete’s body might undersynthesized an antigen.
Too early to tell if there obscure athletic nutritional supplements that may affect the antigen tests. Hard to tell yet if there are/or will be nutritional supplements that mask the test. In time these will be vetted out and possibly banned themselves if they interfer either way with this test.
Maybe there are performance enhancing drugs not known and tested for that effect the antigen production.
Some of these possibilities could be ruled out or alternatively focussed upon and explored further if the test data were known.
It should be harder to accurately detect a recipient phenotypically positive for an antigen receiving blood from a phenotypically negative donor than the other way around since there are a lot more factors that would cause a low antigen population read than a high population read.
It could even be that Tyler transfused or had a medical procedure at a time prior to the expected test detection window, yet found the test was picking up transfusion evidence older than expected. There have obscure instances of transfusion products detected from transfusions as old as 8 years.
Given the newness of the test, it is hard to tell and premature to determine whether Tyler is a victim of an inadequately vetted test or someone caught by the emergence of a test directed at type of cheating he may have engaged in without adequate time or notice to adjust or expectation of detection.