My reply would be, "Ok, so I am an anomaly. Anomalies have a way of debunking common expectations all the way around. So how about we run the tests to figure out what this anomaly is all about?"
Or, in addition, "Do you have any citations on that?"
I know, I know. Black women have serious issues with white male (and sometimes white female) doctors, and speaking with that same assertiveness and claim to authority will get a nasty note in your file, and not likely the needed diagnosis & treatment.
I have a black female friend with multiple chronic disabilities who works as a disability rights activist, and what she's been through with the medical system is shocking. I and many other of her friends do our best to support her and give advice whenever, once again, she has to deal with docs.
As it turns out, the University of Rochester (NY) Medical School has finally seen the racist and ableist assumptions undergirding the treatment of black people and black women in particular, and so they are trying out curricula to educate incoming new docs...AND bringing in more black doctors. They even asked for her opinion. (!!!)
Black voices on medical care are beginning to be added, but of course it is slow paced and concentrated in more advanced medical schools.