19 Screened for TB Had Been Exposed in Past : Public health: None of the Golden West students tested so far has been recently contaminated. Authorities will contact other class members whom they want tested.

Of the 78 Golden West College students screened for tuberculosis last month, 19 were found to have been exposed to the disease in the past, but none had been recently contaminated by an infected classmate, as health officials feared, authorities said.

Those with positive skin tests have had chest X-rays to learn if the disease is active in their lungs, but the results will not be available until later, Dr. Gerald Wagner, Orange County’s interim health officer, said Monday.

The screening was conducted last Wednesday by the Orange County Health Care Agency, acting on the discovery that a student with tuberculosis from La Quinta High School in Westminster had attended a math class during the summer at Golden West. Officials were concerned that he may have exposed the disease to 172 classmates there.

The student, who has been treated and is no longer considered contagious, was one of six juniors at the high school discovered last spring to have had active cases of tuberculosis. The discovery led county health officials to conduct a mass screening at the high school in September. Nearly 1,300 students and teachers were tested; a seventh student was found to have the disease and directed to treatment.

Health officials conducted another screening Monday night from 6 to 9 p.m. at La Quinta for graduates who had not been tested.

The test consists of a small needle prick that is monitored for a couple of days for signs of skin hardening or reddening at the injection spot.

At Golden West, 23 of the 172 students considered to be at risk for exposure showed up for a screening in mid-September, and 78 underwent the second test last month. Wagner said health workers will contact the remaining students to encourage them to be tested either at the college or at the county health department.

The 19 students whose skin tests showed positive had conditions that existed before the outbreak at La Quinta, Wagner said. The screening can show conclusively whether a person has recently been infected, has been treated in the past or has been exposed but not developed any symptoms, Wagner said.

The Golden West students who were tested were mostly immigrants who came from underdeveloped countries or people who have been treated for tuberculosis before, he said.

If X-rays detect the presence of the disease in the lungs, those students will be given treatment that includes a six-month course of medication and follow-up tests, Wagner said.

Golden West spokeswoman Wendy Weber said college officials are “happy with the cooperation we’ve received from the Orange County public health agency. . . . We’re confident they’ve handled the situation skillfully.”

Dr. Penny Weismuller of the Health Care Agency is scheduled to be at Golden West today at 4 p.m. to answer questions concerning tuberculosis and the recent screenings.

The disease, which often displays no symptoms in its early stages, is spread through the air when a person with infectious tuberculosis of the lungs coughs.