WASHINGTON— CLOSE to 10 million people in the United States and Canada seek emergency-room care for chest pains every year. About half of those people are admitted to cardiac units for several days of tests to diagnose heart attack, angina or causes less troubling like indigestion. In the end, fewer than half those hospitalized are found to have heart disease.

These statistics seem to indicate that lives might be saved, patient comfort improved, and time and money conserved if doctors were able to immediately diagnose heart trouble. A patent awarded to a Canadian company for a chest-pain analysis kit that works like a home pregnancy test may give physicians that power.

The kit consists of a palm-size card with a rectangular well in the center for collecting three drops of blood. The well is imbedded with five horizontal strips coated with antibodies. They detect one of four molecules released by the heart during a bout of unstable angina, or continued chest pain while resting, or a heart attack.

The molecules cause combinations of the strips to turn pink. George Jackowski, the chief technical officer for Spectral Diagnostics Inc., based in Toronto, identified the molecules as myoglobin, creatine kinase MB, myosin light chain and troponin.

"When you take a blood sample and put it on the little credit card, if you see myosin light chain and troponin, one or the other or both, we know you're an unstable angina," he said. "If you see myosin light chain or troponin plus myoglobin, then we know that you are early heart attack."

He said the test took about eight minutes from start to finish.

"Twenty years ago, all doctors wanted to do was be able to say, 'Yes, you've had a heart attack,' " Mr. Jackowski said. "But now there are a lot of clot-busters available that if given within six hours of onset of pain can actually prevent heart attack or damage."

Spectral Diagnostics tested the diagnostic kit on blood samples taken from about 600 chest-pain patients in emergency rooms last year.

"We picked up 100 percent of heart attacks in the first blood sample and 87 percent of unstable angina," he said. The company is conducting clinical studies for the kit and hopes to submit its invention to the Food and Drug Administration for approval later this year.

Spectral Diagnostics won patent 5,290,678. Toothbrush Signals Damaging Brushing

Techniques for proper tooth brushing have changed over the years, as have the brushes. After decades of straight-handled, stiff-bristled brushes, Americans can now choose from all sorts of scrubbers with angled arms, indented grips and tiers of rounded, soft bristles. That is because dentists discovered that many people were actually brushing too hard.

To help in this, a Pennsylvania dentist and an engineer have patented a toothbrush with a detector in the handle that sets off a warning signal if teeth are being rubbed so hard that the gums, enamel and even roots are in jeopardy.

"The plastic of bristles is harder than the gum, so the first thing to go is the gum tissue," Dr. Eric L. Spieler, the dentist, said.

While brushes have improved and manufacturers have removed abrasives from toothpastes, Dr. Spieler said, few people are taught the correct brushing pressure.

"Mothers or fathers just tell people to brush, so most people feel brushing harder will remove more plaque," he said. "It turns out that two out of three people brush their teeth too hard."

So, Dr. Spieler and his partner, Richard M. Berman, invented a brush that runs on a three-volt battery. A circuit board and light-emitting diode are mounted in a well on a spring-loaded handle.

"The handle senses movement between the two pieces," Dr. Spieler said. The toothbrush lights up when the sensor gets to a certain level. The brush comes with instructions to "brush your teeth as directed by your dentist, and when you see the light, you know you're brushing too hard, so ease off," he added. "People then get to know the correct level of pressure."

Dr. Spieler said about 70 patients and volunteers were using prototypes of the brush. He and Mr. Berman hope to market it this year. They won patent 5,282,291. Alcohol Calculator To Help Car Drivers

Concern over drinking and driving leads many people to choose designated drivers when they drink alcohol in restaurants or bars. But people driving alone often try to calculate how much they can drink so they can stop before it will affect their driving ability.

Robert Greenlee, a Wisconsin engineer, missed the mark one night and was cited for driving with a blood alcohol level over the legal limit. Rather than make that mistake again, he invented a pocket-size calculating device to measure the amount of alcohol in a person's blood.

"It's meant to be a car key chain," Mr. Greenlee said of his device, which has four punch keys. "You enter your personal information into it once -- male or female, weight, age and height."

That information is stored in a microprocessor. The device then offers a menu of drinks, including beer, wine or mixed drinks.

"You push the drink button and it calculates what that drink will do to your blood alcohol level and displays a green, yellow or red light," Mr. Greenlee explained. "If you are below 0.05 percent, for example, it will be a green light." In many states, a person with a blood alcohol content of 0.10 of 1 percent is considered to be legally drunk.

The calculator will tell a drinker in advance what the next drink will do to his or her blood alcohol level. A red light comes on at 0.08 of 1 percent. The device also shows a user how the blood alcohol level would gradually diminish once drinking is stopped.

"This calculates 80 percent of the population to within plus or minus 15 to 20 percent," Mr. Greenlee said. "So if you stay below the level of impairment, say 0.05 percent blood alcohol level, 15 percent on either side of that should be within the law."

Mr. Greenlee hopes to sell the alcohol calculator for about $25. He received patent 5,274,550.