Analyte measurement

Abstract

A glucose sensor in the form of a skin patch 2 has a microneedle 4 which painlessly penetrates the skin to draw out interstitial fluid. The interstitial fluid passes to a common entrance port 7. A series of microchannels 8 is provided on the skin patch. The fluid drawn onto the patch is selectively switched between a number of microchannels 8 by means of electro-osmotic pumps 10 and hydrophobic gates 12. Each microchannel 8 has an electrochemical detector 11 for sensing gluocse concentration. Also disclosed is a monlithic device with an integrated lance 83.

Description

I. BACKGROUND OF THE INVENTION[0001] This invention relates to apparatus for and methods of measuring certain properties of a fluid particularly although not exclusively, bodily fluids and the concentrations of certain analytes therein. At least some aspects of the invention relate particularly to the measurement of glucose levels in blood and other body fluids such as cutaneous (interstitial) and sub-cutaneous fluid.[0002] Over recent years there have been two obvious trends in diagnostic device development: simplification of the test procedure and reduction in the volume of sample required to perform the test. Test simplification allows the assay to be performed by relatively untrained personnel in a "non-laboratory" setting. Thus, for example, cardiac marker tests configured in a lateral flow immunoassay format with labelled antibody allow for early assessment of potential myocardial infarct.[0003] The driving force for the development of tests requiring smaller sample volumes is...

AI Technical Summary

Benefits of technology

[0017] While not limited to analysing interstitial fluid (ISF), the present invention is preferably used in obtaining and analysing ISF. A further benefit offered by interstitial fluid is that it is not as complex as whole blood and therefore does not, for example, suffer from Haematocrit fluctuations. ISF also has a low viscosity and is more suited to passage through microchannels than whole blood. The low sample volume requirement of a microchannel also enables the device reliably to use interstitial fluid.

[0084] It will be appreciated by those skilled in the art that the arrangement described above is beneficial in its own right in enhancing the signal that may be measured from a minimal sample volume and thus when viewed from a yet further aspect the present invention provides an apparatus for measuring the light from an assay comprising an elongate conduit portion along which a sample fluid is drawn in use and a light sensitive means arranged to be sensitive to light coming substantially from the longitudinal axis of said conduit portion.

Problems solved by technology

Unfortunately, such devices appear to be unable to provide sufficient fluid sample to provide a reliable result and thus, as yet, none has been commercially realised.

Such known devices however suffer from a number of drawbacks, mainly associated with the need to recalibrate the device regularly.

This can negate many of the advantages of using a continuous device since the user is still relied upon to take action in order for the device to operate properly.

Furthermore the accuracy of the devices tends to drift unpredictably between calibrations.

The regular finger pricks are also painful.

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