A 19-year-old Alexandria woman pleaded guilty in U.S. Distric Court in Washington yesterday to mail fraud in connection with a scheme to get more than $213,000 from Blue Cross/Blue Shield by filing false medical expense claims.

The woman, Joanne Margaret Rang of 3110 Mount Vernon Ave., specifically pleaded guilty to her part in picking up a Blue Cross/Blue Shield check for $2,376 that had been made out to a nonexistent individual and mailed to a District post office box.

According to Assistant U.S. Attorney Eric B. Marcy, Rang is one of at least three and possibly four individuals who participated in the scheme, which netted $175,000 in fraudulent Blue Cross payments between September and late October of this year. Another $38,000 in false claims had been filed by the co-schemers but had not yet been paid when Postal Service investigators broke the case on Oct. 29, Marcy said.

More persons are expected to be charged in connection with the case, he said.

According to Marcy, Rang, who was a secretary at the Justice Department until late last month, duplicated forged doctors' bills on U.S. government copying equipment as her part of the scheme. Her handwriting also appears on all 96 false claims submitted, he said.

The scheme was discovered when an employe of Blue Cross/Blue Shield, also known as Group Hospitalization, Inc., noticed a large number of claims filed under one last name. A computer check revealed that large sums had been paid out to individuals with that last name over the preceding month.

Rang, who could not be reached for comment, will probably be sentenced early next year, Marcy said. She faces up to five years in prison and a $1,000 fine.