BDM International Inc., a technical consulting company based in McLean, posted profits of $8.1 million in 1984, a 27 percent increase over earnings of $6.3 million for the previous year.

Earnings per share also rose 27 percent from $1.28 to $1.63. Revenue was $191.4 million compared with $151.1 million in 1983.

"We are pleased with the 1984 results," said BDM President Earle C. Williams. He said the performance proves that BDM "is firmly positioned for future business in key growth areas and has established the credibility and capability to win . . . large multiyear contracts."

BDM provides technical services to national defense and environmental agencies.

* American Management Systems Inc., an Arlington computer services company, yesterday reported 1984 earnings of $2.8 million ($1.70 a share), an increase of 41 percent over 1983 profits of $2 million ($1.21). Fourth-quarter earnings rose to $937,000 (56 cents) from $718,000 (43 cents) in the year-earlier period.

AMS's 1984 revenue was $97 million, a 22 percent increase over 1983.

* Washington's National Bank of Commerce boosted its profits last year by 111.6 percent to $573,777 from $271,291 in 1983 and its assets by 12.7 percent to $69.3 million.