DIY drug testing kits have gone on sale at Newcastle University and other colleges so that students can see what's in the pills they might take.

They're being sold for £3 by the students' union and follows a rise in deaths linked to PMA or PMMA, sometimes found in drugs sold as ecstasy or MDMA.

Experts are warning the packs can't be fully trusted but campaigners insist they can save lives.

Newsbeat decided to put them to the test at a Home Office approved lab.

The EZ test kits are simple to use. You simply snap open the small test tube and put in a small sample of the pill or powder.

Give it a shake and the solution inside should change colour to indicate what the main component of the drug is.

We say "should" because we tried out the ketamine and ecstasy packs but only one of them seemed to work.

Instead of turning red to indicate the main substance was ketamine, the solution went green, suggesting it was amphetamine.

"This is wrong," drug analyst Anca Frinculescu tells us.

"We know this is ketamine, we are 100% sure. The kit is giving us a false reading."

Next, she adds a small sample of ecstasy to the other test tube.

This time, it's more straightforward. The solution immediately turns black, confirming what we already know. The main component is ecstasy.

But as well as having the potential for false readings, Anca tells us users shouldn't read too much into the test results.

"All this tells you is that this substance is mainly ecstasy. It could be 50% ecstasy, it could be 99% - we don't know.

"It doesn't tell us if there's anything else in there too that's even more harmful, something like PMA. It also doesn't tell us the strength of the drug."

Earlier this month, a 17-year-old girl died after taking a strong dose of MDMA, known as "Mastercard" in Manchester.

Two other people were sent to hospital after taking strong ecstasy, shaped like Lego.

These tests couldn't have shown up those risks.

The flip side

But although campaigners from Newcastle's Students for Sensible Drug Policy (SSDP) admit the tests aren't perfect, they argue they can limit the risks.

"They give the user a bit more knowledge about what they're taking than they would have had otherwise," says Holly Mae Robinson.

"If they didn't have the tests they would have taken the drugs anyway.

"But if the drug is mainly PMA, or something other than they thought it was, the tests can tell them and then they can chose not to take it."

Holly Mae questioned the failed ketamine test.

She says "scientifically these tests can't fail" and that only kits past their use by date are unreliable.

Campaigners also dismiss the idea that the kits will make it more likely people will take drugs.

"We're not saying drug use is safe. We're saying the safest thing is not to take drugs," says SSDP Newcastle's founder, Zoe Carre.

"But we're telling people if you are going to use them, you can do it in a safer way.

"We're not giving a false sense of security that the kits are 100% reliable. We've been educating students on the limitations of these tests but we believe they're better than nothing."

They say they've already sold around 100 kits and heard back from one user who says his pill tested as amphetamine rather than MDMA, so he threw it away.

The scheme was approved by the student's union, which is separate to the university.

The university says it doesn't condone any illegal activity and that the safest policy is not to take drugs at all.

It says it aims to balance a tough stance on drugs with the safety and welfare of students.

Holly adds: "If just one life is saved by this campaign, it's worth it."

Ollie McNally is one of the students involved in creating the kit campaign.

Writing on Newsbeat's Facebook page, he says he hasn't seen a test fail in three years of knowing people who use them.

"We make it clear that not finding anything unexpected does not mean the substance is 'safe', and go on to state that should the user still wish to take the substance, they should begin with a very low dose, avoid re-dosing, and avoid mixing substances (including alcohol).

"We also include material to help identify overdoses, as well as various emergency contact numbers and drug-related health information and advice.

"The kits cannot identify high strength MDMA because that would be detecting dose, which is obviously very difficult without complex lab analysis (for pills); but it's beside the point, because we do include information on avoiding overdoses."