A compact device (20) for non-invasively monitoring concentration levels
of blood constituents, including glucose, cholesterol, alcohol, blood gases and
various ions. The device includes a finger receptor (140) having a channel
for receiving a finger of a user. The channel has a light entrance and a light
exit so that light can be passed from a light source (91) through a finger
located in the channel in a direction generally normal to the finger. Certain heat
generating components, including a stable power supply for the device, are external
to the device housing so as to reduce heat generation and thereby increase stability
of the device. The device includes a communications interface for interacting with
a computer. The device can be used for clinical use or for home use and the memory
of the computer can be used to assist with record keeping and with dosage calculations.
