Since insulin's discovery in 1921, steady advances in research, medications and devices of all kinds have helped people with diabetes live ever longer, ever healthier lives.

But cures for type 1 and type 2 remain elusive. And while progress continues, development of an artificial pancreas to match insulin doses with blood-sugar levels could be at least a decade away.

The same holds true for a noninvasive method of testing blood sugar. Prototypes have all proven inaccurate, among other problems, but attempts continue.

The result is that controlling diabetes still requires an arsenal of invasive devices -- including blood-glucose monitors, continuous glucose monitors and insulin pumps -- coupled with a regimen of diet, exercise and medications.

Tight control is doable but difficult.

"I still think it's tough, I really do," said Linda Siminerio, executive director of the University of Pittsburgh Diabetes Institute. "I think diabetes is troublesome 24/7 because it never leaves you."

Dr. Siminerio and others familiar with diabetes technology agree that available medications and devices work best when people adapt them to a healthy lifestyle.

But diabetes still turns people into human pin cushions, with insulin injections, lancet pricks to draw blood and cannula insertions to operate insulin pumps and continuous glucose monitors.

Insulin pumps provide a steady flow of insulin to the body, making injections unnecessary. But they also require insertion of a flexible tube or cannula under the skin with a pump attached to the clothes or, in newer models, attached to the skin.

Blood-glucose monitors provide quick and fairly accurate readings but require pricking a finger or drawing blood from the arm or another area of the body to complete the test.

Continuous glucose monitors, the latest rage in diabetes control, provide readings every few minutes, showing patterns in blood-sugar levels. Because these monitors test glucose in interstitial fluid under the skin, rather than blood, real-time accuracy is not possible and traditional blood-glucose meters must be used to calibrate the monitors and provide baselines.

Continuous monitors, like pumps, also require insertion of a cannula once every few days; should be worn around the clock; and still may require occasional booster injections.

But tight control is worth the effort. Studies reveal uncontrolled diabetes can trim life expectancy on average up to 15 years.

"You can have the best technology out there, but it's how you use that technology that counts," said Dr. William Hsu, a medical doctor and professor, clinical researcher and director of the Asian Clinic at the Joslin Diabetes Center in Boston. "Glucose meters give the best results, but if you don't use the results to impact your lifestyle, it's ultimately not going to matter."

Prime numbers

Control is a daily, even hourly, balancing act for people with diabetes. If blood-sugar levels are too high, they must take insulin, exercise or refrain from eating to drop levels back to normal. If blood sugar dips too low, they must consume sugar, carbohydrates or glucose tablets to raise it out of the danger zone.

The key to control is taking corrective action based on blood-sugar readings.

With type 2 diabetes the body no longer efficiently uses its own insulin -- the hormone produced in the pancreas that allows glucose to enter cells and be turned into energy. Glucose buildup in the blood without treatment can lead to coma or death.

Type 1 diabetes, an autoimmune disorder that typically appears in childhood or slightly later, destroys the pancreas' ability to produce insulin, requiring insulin treatment for a lifetime.

Meters that measure blood glucose weren't even available until the late 1970s. Representing a breakthrough in at-home control, the early systems were riddled with timing and procedural errors affecting accuracy.

In the late 1980s, a new method emerged that remains in use. Using a static electrochemical process, a current sent through the blood sample measures glucose levels with an accuracy rate within a plus-or-minus 20-percent international standard.

Recent advances make the process easier. Inserting a strip into the meter turns it on. Once the finger is pricked, the strip draws in the blood and the meter provides results in seconds.

Roche Diabetes Care's Accu-Chek line is the world's most popular brand of glucose meters, but OneTouch meters made by LifeScan remain the nation's most popular.

Most brands boast they use minimal blood, provide results in seconds and offer blood-sugar trends for a week, month, 90 days, and before and after meals. Experts warn that different models offer features that might better fit a person's needs, so some shopping for the most suitable equipment is important. Also, health-care providers often pay only for specific brands.

Accu-Chek's Compact Plus meter has 17 test strips in a drum, so one does not need to insert them for each test. It also has a lancing device attached to the meter to draw blood with less pain. LifeScan's Ultra Mini, among other innovations, has taken glucose meters into the fashion era with such colors as limelight, pink glo, jet black and silver moon.

Meters now exist for virtually any need, preference or goal. But the pain of pricking a finger and drawing blood deters many from testing their blood sugar. The Pennsylvania Department of Health says only 60 percent of people with diabetes test blood sugar at least once a day, indicating widespread lack of control. Jeff Christensen, LifeScan's communications manager, said two-thirds of all people with diabetes are uncontrolled, despite the tools available.

For those in control, and on insulin, lack of pinpoint accuracy in blood-sugar readings is a concern. A reading of 80 to 100 milligrams per deciliter is normal. So a reading of 82 -- the lower end of the normal range -- might suggest a delay consuming food or sugar for a while. But the potential 20-percent variance in accuracy means the actual reading could be as low as 65, which means blood sugar is already too low.

AgaMatrix Inc., a Salem, N.H., company, boasts it makes the world's most accurate meter, with a plus-or-minus 10-percent accuracy for most tests. Sonny Vu, chairman of the board and a founder of AgaMatrix, said he foresees the international standard, now 20 percent, eventually dropping to 5 percent..

WaveSense, the "dynamic electrochemical" technology it developed, neutralizes differences in blood, eliminates effects from chemicals and temperature, and even adjusts for sugars on the skin that can affect readings. The system automatically corrects for errors.

Dr. Barry H. Ginsberg, recently retired medical director of Worldwide Diabetes Care and current president of Diabetes Technology Consultants in New Jersey, said a perfectly accurate machine would be the size of a television set, so a degree of error is unavoidable.

Nonetheless, Mr. Vu claimed his meters are edging ever closer to perfection.

"There's an arms race to make it faster and more faithful," he said.

Insulin delivery

Various companies produce insulin pumps -- devices that provide a steady dose of quick-acting insulin to help control diabetes without injections.

Dr. Hsu said OmniPod produced by Insulet Corp. of Bedford, Mass., is cutting-edge. Launched two years ago, the pump is less than an inch thick and is only 1.6 inches wide and 2.4 inches long. Operated with a wireless remote, the pump has no tubes connecting its different parts and sticks to the stomach or upper arm with an adhesive. It causes less pain by automatically inserting a cannula. The OmniPod is used three days, then discarded. A blood-glucose meter also is attached to the remote control for convenience.

OmniPod represents the latest in the long march toward an artificial pancreas. In fact, the company says it will soon will add a continuous glucose monitor produced by Abbott Laboratories to the system that would be controlled by the same wireless remote that operates the pump.

"With diabetes and devices in general, the trend is toward user-friendly -- devices that look and feel like mainstream electronic devices," said Elisabeth Vivaldi, director of marketing for Insulet Corp.

Medtronic Diabetes in Northridge, Calif., sells more insulin pumps and continuous glucose monitors than any other company in the world. It, too, is refining its insulin pump to be tubeless and already has wireless control to regulate how much and how often insulin is delivered.

"Everybody is heading toward the patch pump," he said, noting the device that OmniPod developed. We're very close."

Blood-sugar trends

The latest device to emerge on the market offers yet another option for people with diabetes having trouble with control.

The continuous glucose monitors provide trends around the clock, rather than the occasional readings from blood-glucose meters. Continuous monitors also send an alarm when levels swing too high or too low.

Medtronic sells the most, but DexCom Inc. also offers a continuous monitor not much larger than a quarter. The Food and Drug Administration has approved use of continuous monitors for children and cleared the way for a model that is worn for seven days. Most current brands operate for three days.

But systems can cost thousands of dollars, with additional monthly costs that health-care providers don't always cover. While providing people with another means of control, it also requires wearing yet another device.

Accuracy remains a major obstacle.

"Understanding why they are not accurate and figuring out what the lag is and how to correct for it" is what's necessary to improve such monitors, Dr. Ginsberg said. "When they figure that out, we can predict the future."

Electronic pancreas

"The Holy Grail with diabetes is the artificial pancreas and Roche is working on the necessary components," said Jennifer Aspy, director of product marketing and operations for Roche Diabetes Care.

Dr. Alan Marcus, Medtronic Diabetes' vice president and global director of medical affairs, said his company is developing an artificial pancreas in steps. The first step, expected within two years, automatically will adjust insulin doses and sound an alarm when sugar levels dip too low. The second step will add insulin and provide an alert when sugar levels go too high. The third step will involve keeping sugar levels consistently in the normal range.

"There's no crystal ball, but we're close," Dr. Marcus said.

Such a system would be based on glucose readings from interstitial fluid under the skin rather than blood, as done by continuous glucose monitors. The artificial-pancreas puzzle will be solved eventually, Dr. Marcus said, by retranslating real-time blood sugar levels into interstitial fluid readings.

Once a reliable artificial pancreas is developed, the Food and Drug Administration would have to test and approve it before it could be marketed.

But Dr. Ginsberg argues that "a pure closed loop" -- an artificial pancreas that operates accurately without human input -- "will never come about. ...There's never been an artificial organ better than the body itself."

A person's body knows when he or she is about to eat because it receives signals from the intestines to begin releasing insulin. Signals regulating insulin also are generated when the body is exercising. "Current devices won't do that," he said.

So human input will remain paramount.

"Generally people have to come with the desire to take control of diabetes," he said. "I think we have come to a place in diabetes care where people who want to be in control can be in control."

Or as Dr. Hsu noted, "We've come a long way since insulin was discovered.

"The goal is a cure," he said. "But short of a cure, technology helps to manage diabetes without interfering with life."