Thomas Rice {"Medicare: A Fixed Fee for Doctors," op-ed, Dec. 15} rightly points out that Medicare Part B premiums will rise by 38.5 percent in 1988. Despite the fact that physician fees were frozen in 1984, he points the finger of blame at the medical profession. He fails to point out the following facts:

1. This is the first increase in premiums in three years.

2. Medicare Part B spending is up 20 percent, representing only approximately one-half of the premium increase.

3. The increase of 20 percent is due to a number of factors including:

a) the fact that Congress has legislated more prompt payments by the insurer;

b) Congress updated Medicare payments to patients, physicians, suppliers, laboratories and other nonphysician providers;

c) there are more Medicare beneficiaries each year;

d) more services are available to our Medicare population -- an example: two patients of mine who are in their eighties have recently had hip replacements, enabling them to continue living independently. Would Mr. Rice ration such care and thereby diminish the quality of life and increase the non-Medicare Part B cost of care for these people?

Congress froze physician Medicare fees in 1984, though in 1987 I was permitted finally to raise my office visit charge by 40 cents. This will be essentially eradicated by Gramm-Rudman. Having a sizable Medicare constituency among my patients, my gross income has remained relatively flat over the past three years, and my net income has diminished. It would have diminished even more had I not asked my younger patients to subsidize in some very small part their elders.

I grow weary of defending myself and my profession against the physician bashers. Doctors are not perfect, and we welcome fair and constructive criticism, which this article was not.

JAMES E. FITZGERALD, M.D. Washington