The first continuous glucose monitor could be on its way to doctors' offices. MiniMed will ask the FDA this month to approve its application for the continuous glucose monitoring system.

This is not the end of finger sticks. The machine does not tell you what your blood sugar is, so you must do your normal, everyday testing. Only a doctor can get information from this system.

The system must also be calibrated every day with one finger stick. The monitor reads glucose levels 288 times every 24 hours. It stores these readings into a receiver box the size of a large pager.

Although it can store readings for a maximum of 14 days, MiniMed's recommendation is that people bring it to their doctors after three days. The doctor then uploads the data to a computer and analyzes highs and lows to adjust the person's treatment regimen.

Interstitial Fluid

By keeping a probe inserted just below the surface of the skin, the system constantly measures the glucose levels in the body's interstitial fluid (ISF). MiniMed (and other companies working on meters that measure ISF) says that glucose levels in the ISF and glucose levels in the blood are close enough for good diabetes management.

Some say that ISF glucose measurement is not good enough. One study, led by a MiniMed competitor, concludes that ISF research has not yet been proven reliable enough and that more research needs to be done before ISF measurement can be used for glucose monitoring (Critical Reviews in Therapeutic Drug Carrier Systems 15[3] [1998]: 199-241.). The study says that the blood glucose can be rapidly rising or falling but these changes don't show up in the ISF until much later. They say this time lag puts people in danger, particularly of becoming hypoglycemic.

MiniMed president Terrance Gregg says that in his company's clinical tests, the longest time lag was only 10 or 12 minutes. Gregg calls ISF glucose levels "physiologically important," as the ISF glucose is the glucose that actually feeds the cells of the body.

The FDA must now decide if the measurements of the continuous glucose monitoring system are accurate enough for diabetes health care professionals.

FDA To Decide

Many concerned people, and companies in the new technology monitor race, will be anxious to hear the FDA's decision on MiniMed's new system. The FDA meeting is schedule now for February 26 from 8 a.m. to 5 p.m. at the Gaithersburg, Maryland, Marriott and is open to the public. The FDA invites interested persons to present written or oral testimony, but it must be approved before February 12.

To get an update on the meeting, call the FDA Advisory Committee Information Line at (800) 741-8138. The meeting code is 12514.

MiniMed's First Step

Gregg calls this the first step in the evolution of a continuous glucose sensor for home use. He predicts the home sensor to arrive in the year 2000.

The final goal is the artificial pancreas, in which MiniMed hopes to combine the continuous monitor with its insulin pump technology. The artificial pancreas is predicted to measure glucose levels constantly and automatically adjust insulin dosage.