New York designer Adolfo made an informal visit to his friend Nancy Reagan's home in Virginia last weekend. Strictly a social call, insists the Cuban-born designer whose clothes Mrs. Reagan probably will wear most frequently in the White House.

Adolfo, who was working with buyers in his second-floor Madison Avenue showroom on Election Day, would only say, "Let's only discuss the present, not the future. It's bad luck."

Since Nancy Reagan's pal Betsy Bloomingdale introduced her to Adolfo in 1967, Mrs. Reagan has bought about 10 items a year from him. She seems to prefer his Channel-style suits but also buys his dresses and coats as well. He currently is making her a one-shoulder, black velvet evening dress with a huge puffy sleeve. "It was not ordered for any special occasion, but just to have," insists the soft-spoken designer.

While she is frequently photographed in Adolfo's designs, Nancy Reagan also wears clothes by European designers Valentino and Saint Laurent, plus Pearl Nipon, James Galanos, Bill Hayes and Jean Louis (it was a Jean Louis dress that she was wearing Election Night.)

A perfect size six, according to Adolfo, Mrs. Reagan usually comes to his Madison Avenue studio twice a year to make her selections. "She says she is coming up to see my dogs," says Adolfo. He has two pugs, Alexander and Victoria, who trail him as he races about in his white cotton medical lab coat, pins in the collar, tape measure around his neck. He is rarely without a thimble on his right hand, except recently when he feared he had swallowed it. No he always carries a spare in his pocket.

To relax, he likes to go to lunch at La Grenouville "and count all the ladies wearing my suits," he teases. It delights him to see women wearing his vintage designs, as Mrs. Reagan often does.

Adolfo, whose clothes are what he calls "modern, custom ready-to-wear," sells through stores like Saks Fifth Avenue in Chevy Chase. They carry samples of his styles that can be ordered according to color preference. Adolfo clothes take four to six weeks to make up in his factory on Long Island. And they retail from $695 to $995 for the suits, $700 to $1,200 for the evening clothes.

He charges the same price for his private customers on Madison Avenue. Even the Duchess of Windsor, never known for prompt payments of her fashion purchases, respected Adolfo's strict business discipline and paid her bills promptly.

It is Adolfo's signature knit Chanel-style suits with contrast braiding that Mrs. Reagan orders -- often with an extra silk skirt to wear with the suit jacket. He comes by this look legitimately. He worked for Coco Chanel in Paris before coming to New York, where he got his first job making hats at Bergdorf Goodman. (Halston took over the millinery slot at Bergdorf's when Adolfo left.) "I never liked to make hats, but did it out of sheer necessity," he says. He made hats for Jacqueline Kennedy while she was in the White House -- though she only started wearing his clothes after she became Mrs. Onassis.

Other Adolfo faithfuls in Washington include Buffy Cafritz, Connie Mellon, Ross Cass and a lot of wealthy women whom Adolfo describes as "wonderful women who six years ago couldn't afford my things. Now they buy them six at a time."

Adolfo also has his name on a line of jeans, sportswear for women, menswear, fragrance for women, and soon a fragrance and toiletry collection for men.

"This [licensing] company is so greedy and horrible," he says. "They want me to show the men's clothes and test the cologne for men on Governor Reagan. They don't know I don't work that way."