Hundreds of people received letters of warning this week from the state and Nassau County health departments, advising them to be tested for HIV and two strains of hepatitis, due to risky injections by a Long Island anesthesiologist.

Dr. Harvey Finkelstein, an anesthesiologist at Plainview Hospital in Nassau County, N. Y., allegedly reused syringes while injecting patients with pain medication, thus placing them at risk for infections with HIV, hepatitis B and hepatitis C, county and state officials said earlier this week.

The state and Nassau County health departments alerted 628 patients by letter this week that they should be tested for HIV, hepatitis B and hepatitis C infection. All these patients were treated by Finkelstein between Jan. 1, 2000 and Jan. 15, 2005, according to health officials.

The anesthesiologist first came to the attention of a state health investigation in 2005, after two of his patients contracted hepatitis C. His case was reportedly referred to the State Board for Professional Medical Conduct of the State Education Department some nine months after his unsafe practices had become known, according to the New York Times.

While Finkelstein used a new syringe for each patient, he would use one syringe to draw doses from vials of medicine that contained multiple doses, thus compromising their safety. During an injection, a very small amount of the patient’s blood may enter the syringe – if reused, it can carry the blood to another patient.

Finkelstein told investigators that he began using one syringe to draw from multiple vials in 2000, according to the Times.

A State Health Department spokesman told the paper that the anesthesiologist was instructed in 2005 how to administer pain medication adequately by syringe and he has been monitored ever since.

Newsday reports that state health officials found infection controls in the state-licensed clinics where Finkelstein had administered injections were satisfactory, leaving only his private practice in need of investigating. All of the 628 patients notified this week are from Long Island, except for 12, according to Newsday.