GENTLE METHOD OF PHLEBOTOMY AND ASSAY

Skin fragility and a tendency to excessive bleeding among older people impose special problems in drawing routine blood samples. The design of the blood sampling and assay system described here addresses these problems by using an integrated needle and microcuvette consumable to draw a sample of less than one microliter and perform the assay with this volume. During Phase I, experimental consumable of this design will be made by silicon microfabrication technology and evaluated in needed strength tests and glucose assays. Devices differing in the outside diameter, bore, wall thickness, and length of the needle will be made. The key aim is to obtain a correlation between the strength of the needle and these mechanical parameters. A subsidiary aim is to demonstrate a glucose assay with whole blood in consumables of this design. Consumables with favorable combinations of properties, as determined by these tests, will then be fabricated and tested. In this iterative manner, the development program intends to progress toward consumables having such fine needles (less than 100 micrometer diameter) that the sampling process is likely to be nearly painless. Further development of this novel technology offers the benefits of painlessness, sub-microliter sample volume, immediacy of the result, low cost, ease of use, and ability to assay many analyses.