A proctologist deals with the rectum & anus.
(For CSI fans, I learnt this when Gil Grissom joked that he'd been to see a proctologist after the sheriff was being a pain in the a...)
A gastroenterologist or a proctologist.
Immunologist
The name of a neck doctor can vary on the type of treatment you are looking for. You could be referring to an ENT, a chiropractor, or an orthopedic doctor.
It's simple ask your Doctor for a "blood type" blood test. If your doctor has ever done blood work on you, he might have your type on file already!
Chromosomal disorders can be observed in a human karyotype. It can show whether there are extra chromosomes, or missing chromosomes, or malformed chromosomes, or whether chromosomes have extra pieces, or missing pieces.
In order to accurately determine blood type, blood must be drawn from the donor. This means that only a doctor or assistant can accurately tell a donor what blood type they have.
geneticist
A gastroenterologist is a physician specialist in the treatment of diseases and disorders of the digestive system. A gastroenterologist may also be called a GI specialist (gastrointestinal specialist).
A cardiologist is a heart specialist and a pulmonologist is a chest/lung doctor.
Gastroenterologist.
A rheumatologist
dermatoglist
Cardiologist.
A general practitioner is the type of doctor that treats the largest range of ailments. A general practitioner treats all ages of patients from birth to the very aged.
neurologists
There isn't a type of doctor who specifically treats doctors.
Immunologist
orthopedic surgeon