This is from the "Technical Instructions for Medical Examinations" that the civil surgeon uses.
Summary - anyone with a Class A condition can be denied AOS ( so its typically a 485 thing).
Here is the actual text:
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212 "(a) CLASSES OF EXCLUDABLE ALIENS.- Except as otherwise provided in this Act, the following describes classes of excludable aliens who are ineligible to receive visas and who shall be excluded from admission into the United States: "
(1) HEALTH-RELATED GROUNDS.-- "
(A) IN GENERAL.-- Any alien--
"(i) who is determined (in accordance with regulations prescribed by the Secretary of Health and Human Services) to have a communicable disease of public health significance,
"(ii) who is determined (in accordance with regulations prescribed by the Secretary of Health and Human Services in consultation with the Attorney General)--
"(I) to have a physical or mental disorder and behavior associated with the disorder that may pose, or has posed, a threat to the property, safety, or welfare of the alien or others, or
"(II) to have had a physical or mental disorder and a history of behavior associated with the disorder, which behavior has posed a threat to the property, safety, or welfare of the alien or others and which behavior is likely to recur or lead to other harmful behavior,
"(iii) who is determined (in accordance with regulations prescribed by the Secretary of Health and Human Services) to be a drug abuser or addict, is excludable."
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Also this
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SCOPE OF THE EXAMINATION The purpose of the medical examination is to determine whether the alien has 1) a physical or mental disorder (including a communicable disease of public health significance or drug abuse/addiction) that renders him or her ineligible for admission or adjustment of status (Class A condition);
or 2) a physical or mental disorder that, although not constituting a specific excludable condition, represents a departure from normal health or well-being that is significant enough to possibly interfere with the person's ability to care for himself or herself, or to attend school or work, or that may require extensive medical treatment or institutionalization in the future (Class B condition).
Thanks !