Eight teenagers have had blood tests after being pricked with a syringe at a Sydney high school in a “prank” that saw emergency services race to the scene in the city’s west.

Ambulance and police crews were called to Plumpton High School, about 50 kilometres from Sydney’s CBD, about noon on Thursday after reports that several people had been stabbed with a syringe.

But NSW Police later reported that a student appeared to have pulled a “prank” and the eight students each received only “a minor needle prick”.

Two students were reportedly taken to Mt Druitt Hospital. Others were taken to a medical centre with their parents to undergo tests as a precaution, police said in a statement.

The students may now have to wait several months to find out if they are clear, after a full round of blood tests.

The NSW Department of Education confirmed a student “attended school with an implement” that was used to prick others.

“The school will be taking strong disciplinary action against this student,” a spokesman said.

Police are investigating the incident, he said. Staff and students are also being offered counselling and support.

Acting Inspector Shane Rolls described the injuries as “minor”.

“While this is very concerning behaviour, we want to reiterate that no students were stabbed as initial inquiries first may have led people to believe,” he said.

“At this stage we would believe it was a prank gone wrong.”

Police are yet to speak with the alleged offender, but warned they would pursue the matter if they could establish whether the student had acted with any ill intent.

“We will certainly be looking into if there was any malicious intent in this incident.”

NSW Ambulance claimed the alleged offender picked up the syringe from a bus stop, but Acting Inspector Rolls said that was still being investigated.

Joe Ibrahim from NSW Ambulance said the risk was “quite low”.

“The puncture sites … were sort of quite minimal,” he said.

Mr Ibrahim compared the tests to when ambulance officers are potentially exposed to disease risk on the job.

“The first blood test is a baseline test and you do worry about that for up to three months. It’s quite concerning,” he said.

-with AAP