Nicholas Lambis, 27, a part-time personnel clerk at the National Institutes of Health for the past six-years, died at NIH Tuesday of Beta-thalassemia major, or Cooley's anemia.

As a patient at NIH for the last 14 years, Mr. Lambis "made a substantial contribution" to efforts aimed at controlling the disease that took his life, according to one of his physicians, Dr. French Anderson, a hematology program chief at NIH.

The disease is hereditary and manifests itself as an inability of the body to produce its own blood.

Until the drug Desferal was tried as a possible treatment for Cooley's anemia at NIH in 1973, the life span of a patient with the ailment was seldom more than 13 to 15 years.

The primary treatment has been blood transfusions and Dr. Anderson said that in most cases the body was unable to assimilate the iron that accompanied the transfusions. As a result, he said, most patients would suffer cardiac arrest.

With the development of Desferal, patients were able to continue transfusions without the side effects of excessive iron, Dr. Anderson said. He said the life expectancy of Cooley's anemia patients is now far longer than previously.

He added that Mr. Lambis had donated much of the blood required in experiments to advance treatment of the illness.

In 1965 Mr. Lambis' blood was used in experiments that showed that blood cells of patients with Cooley's anemia could not make a normal hemoglobin molecule. In 1977, his blood was used in experiments showing that an iron-binding drug could improve treatment of the disease.

"As a result of his contributions as a patient in early studies of new therapy for Cooley's anemia, Mr. Lambis is now a widely known person in medical circles," said Dr. Anderson.

Mr. Lambis was born in Washington. He was diagnosed as having Cooley's anemia when he was less than a year old. After undergoing treatment at Children's Hospital he bacame a patient of Dr. Anderson, and in recent years, of Dr. Arthur Nienhuis at NIH.

Despite his illness, Mr. Lambis graduated from Calvin Coolidge High School in 1971 and attended Montgomery College.

Survivors include his mother, Eugenia, and a sister, Judy, both of Washington; four other sisters, Jenny Fytras of Brooklyn, N.Y., and Phyllis Axarlis, Judy and Barbara, all of Silver Spring, and two brothers, Constantinos, of Falls Church, and James, of Silver Spring.

The family suggests that expressions of sympathy be in the form of contributions to NIH Patients Emergency Fund.