An incubator includes an incubator ring assembly having at least two concentric rings supported for rotation about a common axle defining an axis of rotation. Each concentric ring includes a plurality of circumferentially defined load positions, each load position being sized for accommodating a test sample. At least one test station is arranged in relation to the plurality of load positions to selectively test a test sample, the test samples being are sequentially shuttled into and out of load positions of at least one of the concentric rings to increase the overall throughput of the analyzer.