Navigator Approved

Abbott's Navigator continuous glucose monitor (CGM) has finally been approved by the Food and Drug Administration. The device was approved in Europe last June, but US FDA approval has been stalled for several years for reasons that are unclear.

Every month or so, it seemed, there would be an announcement by Abbott that FDA approval was expected "soon," and some people began to think it would never happen.

But now it has, and the Navigator will be available for purchase sometime later this spring.

This means that those who wish to use a CGM will now have a choice of three brands: the Abbott Navigator, the DexCom Seven, and the MiniMed Guardian REAL-Time system. One hopes that competition will bring the prices down.

Currently the DexCom kit lists at $800 and includes the receiver, transmitter, software, carrying kit, cables, and battery charger. Sensors are sold in four-packs (about month's worth), for $240, or $60 each, for a total price of $1040. However, they're currently having a special of $295 for the kit if you buy a four-pack of sensors at the regular price (total price of $535).

Each sensor is FDA-approved for seven days, but many people say they can get them to last longer. The long times aren't recommended, however, because of the risk of infection.

The Guardian REAL-Time lists at $1339, including a month's worth of 10 three-day sensors. The kit includes basically the same things as the DexCom, except that the free CareLink software is Web based.

Minimed also sells a CGM system that is integrated with a pump.

The new Abbott Navigator will be priced between $960 and $1040, according to an Abbott representative. This will include a month's supply of six sensors and presumably the same accessories as the other brands. Sensors alone will cost $360 to $390 a month.

All the systems basically do they same thing. They insert a sensor into the interstial fluid in your subcutaneous fat. The sensor measures your blood glucose (BG) level every few minutes and transmits that information to a receiver that is about the size of a small insulin pump. The receiver displays the BG level on the receiver and also shows trend graphs of your BG levels for the past hour, several hours, and up to 9, 12, or 24 hours, depending on the brand.

The devices have alarms that sound when your BG levels go too low or too high (you can determine when you want the alarms to go off, although there may be a low-BG alarm that you can't turn off). The Navigator and the Guardian also have trend arrows that tell you if your BG levels are steady, rising, or falling. The current version of the DexCom does not have the trend arrows.

The BGs can also be downloaded to software that allows you to print the results or do various manipulations of the data.

In order to calibrate the CGM receivers, you have to let it know what your fingertip BG level is a certain number of times a day. The new Navigator has a Freestyle BG meter built into the receiver. The Guardian has you input the BG levels manually. The DexCom currently uploads BG levels with a cable from an Ultra BG meter. A new version of the software for the DexCom due out in June will allow you to input the numbers manually so you can use any meter.