Pacesetter of Sylmar, Calif., has received US Patent No. 8,192,360, "Implantable body fluid analyzer."An implantable microarray device is described that includes an inlet for a body fluid; individual reaction cell arrays where each reaction cell array includes a series of reaction cells configured to receive the body fluid; a sensor array to sense a reaction result for an individual reaction cell array; and a positioning mechanism to position an individual reaction cell array with respect to the sensor array.