Your question begs some clarification.

If your huband "was" in Qatar, where is he now? And why you need a medical exam for? If you come here with intent for employment and you are processed through any agency in the Phils then your agency will advise you where to get that medical exam.

Once you get that employment, your employer will have you undergo another medical exam with Hamad Hospital as a requirement, and you have to pass that exam in order to be granted residence permit.

If you are just plain visitor because your husband "was" here, then you dont need that medical exam.