Do you think you can wash your hands clean of bacteria? According to a new study published in the journal Infection Control & Hospital Epidemiology, you probably can't — and it's possible your doctor and nurse can't, either. Researchers at Glasgow Caledonian University in Scotland watched the different hand-washing techniques of doctors and nurses and measured the bacteria on their hands to determine what is the best approach. It turns out many of them don’t complete the necessary steps.

"Hand hygiene is regarded as the most important intervention to reduce health care-associated infections, but there is limited evidence on which technique is most effective," said the study’s lead author Jacqui Reilly, a professor of infection prevention and control at Glasgow Caledonian University in Scotland, in a statement. "This study provides a foundation for effective best practices to implement on the frontlines of health care."

For the study, researchers observed a random selection of 42 doctors and 78 nurses at an urban teaching hospital. Printed on the walls in front of every washing station is a six-step technique that was determined by the World Health Organization (WHO) to be most effective at reducing bacteria. But in reality, only 65 percent of doctors and nurses studied complete this entire hand washing process. Instead, they more closely followed the three-step hand washing technique provided by the Centers for Disease Control and Prevention (CDC).

Rubbing your hands together with soap is just the first step, and although most people follow it, they stop, rinse, and miss a significant opportunity to disinfect themselves. The key is in the rubbing. According to the six-step technique, you’re also supposed to rub the backs of your hands, in between fingers, on the back of fingers, around the thumbs, then along the palms of the hands.

The CDC, on the other hand, recommends washers lather their hands by rubbing the backs of hands, between fingers, and under nails for 20 seconds, which is about the same time it takes to hum the “Happy Birthday” song from beginning to end. Then rinse your hands under running water, dry them, and you’re done.

The WHO’s six-step technique was able to reduce 21 percent of the bacteria on average (from 3.28 to 2.58 colony-forming units per milliliter), while the CDC’s three-step technique was only able to reduce 6 percent of the bacteria (from 3.08 to 2.88 CFU/mL). Ultimately, the researchers said that even though the six-step technique to reduce bacteria was nearly four times better than the more commonly practiced one, it still took an average of 42.5 seconds longer.

According to the CDC , handwashing before eating and drinking, and after using the bathroom are some of the most important times to clean up. Germs from unwashed hands can get into foods and drinks, onto toys and table tops, transfer to another person, and eventually make others sick. Approximately 31 percent of people get sick by coming in contact with diarrhea, and another 16 to 21 percent fall sick from respiratory illnesses like colds, which are spread by germs. Reducing the greatest amount of bacteria possible is essential to keeping communities healthier.

"One of the interesting incidental findings was that compliance with the six-step technique was lacking," Reilly said. “Only 65 percent of providers completed the entire hand hygiene process despite participants having instructions on the technique in front of them and having their technique observed. This warrants further investigation for this particular technique and how compliance rates can be improved.”

Source: Reilly JS, Chow A, and Price L, et al. A Pragmatic Randomized Controlled trial of 6-Step vs. 3-Step Hand Hygiene Technique in Acute Hospital Care in the United Kingdom. Infection Control & Hospital Epidemiology. 2016.