NEW ORLEANS - Will those automatic machines in retail stores give you an accurate reading of your blood pressure?

Eyewitness News had a doctor go out with our crew to verify.

Research shows those automated blood pressure machine next to pharmacies are not reliable or accurate. Tulane's Dr. Paul Whelton and Harvard Men's Health Watch editor Dr. William Kormos, say the same. And since so many people depend on them for a free and convenient reading, Eyewitness News decided to verify their accuracy.

The camera rolled at the Mid-City Winn-Dixie, at the machine next to the pharmacy. With our verify team, is Dr. Cathi Fontenot, an internal medicine specialist at LSU Health Sciences Center. She was armed with her manual blood pressure cuff and stethoscope.

One by one grocery shoppers were randomly asked to join our verify experiment.

"Your heart, I mean, your blood pressure is something you definitely need to keep up with, you know. I've done had that problem before but I'm on top of it now," said Jeffery Parker.

"I know that your blood pressure can cause you to have a heart attack. It can cause you to have a stroke. If you have diabetes, it's going to run your diabetes higher. I know all of this. Yes. Very educated about it," Wanda Parker, Jeffery's wife, said with a chuckle.

"Every Tuesday I get my pressure checked, just to be on the safe side," said Yvette Robinson.

The random sample of shoppers were very knowledgeable about the dangers of the silent killer. They each agreed to get their blood pressure reading on the automated machine first, then immediately after, Dr. Fontenot took it the old fashioned, manual way.

First, the medical verify test made a difference in some lives. While some already knew they had high blood pressure and take medication daily for it, some had no idea.

"I just had a knee replacement and I'm taking Celebrex, so normally I've never had high blood pressure and it was a little bit higher than normal. So she (Dr. Fontenot) said anti-inflammatory drugs sometimes can increase blood pressures," said Linda Gidday

"I would say slightly higher, but nothing to be alarmed about, but I should just come in and check it like once a week to make sure that it's stable," said Richard Waldrup after learning his pressure was a little higher than it should be.

And just to show why you need a reading, a lean, 26-year-old, avid runner, has high blood pressure.

"I have a family history of high blood pressure on both sides. And I do have a low resting heart rate, but probably could eat a little healthier, you know, kind of been breaking the rules with Mardi Gras and everything," said Physical Therapist Barbara Baldwin.

"High blood pressure comes in all shapes and sizes, you know. You can see it in thin people. You can see it in overweight or obese people, but you don't have to be big to have high blood pressure. A lot of it really is genetic," explained Dr. Fontenot.

The automated machine at Winn-Dixie was accurate. In all six volunteers, the machine and doctor's numbers were almost identical. But there is reason why the one we tested is accurate and others might not be.

"About every three to four months, our corporate headquarters sends someone down and they calibrate it, and that's something that we really make sure that we get done often," said Mid-City Winn-Dixie Pharmacy Manager Sandy Bissant.

So what happens when they don't get calibrated regularly?

"If it's not calibrated, it can give you a false reading, so then it gets people more upset," Bissant continued.

You can get a false high or false normal. The problem is the machines are one-size-cuff-fits-all so a very large or very small arm would not get an accurate reading.

So while doctors say phone apps, finger and wrist monitors are not accurate, Eyewitness News can verify that you can get an accurate reading on store machines if and only if the pharmacist verifies that the machine is calibrated regularly.

Doctors say for every two pounds you lose, you can expect the top number of your blood pressure to go down by one point.

For Heart Health Month through February, all generic heart and blood pressure medications are free or $2 at all Winn-Dixie pharmacies.