A densitometer based on a microcomputer and TV camera, for use in the clinical laboratory.

We describe a microcomputer-based densitometer that includes a television camera for the analysis of one- and two-dimensional electrophoresis gels. The hardware configuration is a modification of that described by Mariash et al. (Anal Biochem 212: 388-394, 1982). The video signal is digitized by a commercially available interface, yielding 1 of 64 greyscale values for each pixel examined. The operator controls the region being analyzed through the use of a joystick and video monitor. We have optimized the linear response range (0-1.5 A) and have written a relatively simple control program ("GELSCAN 5.0"). For analyses of one-dimensional gels, the required operator decisions include the start and finish points of the gel, the width of the scan (analogous to slit size), and the level of background correction. The digital information may be stored on disk, displayed by one of several graphic routines, and analyzed for total scan and individual peak absorbance values. Similar analyses may be done with two-dimensional gel spots.