A method for selecting an empty cell (20,602) to place an incoming specimen container in a test instrument, comprising: electronically determining and/or obtaining cell availability of cells of a holding structure in an incubated test chamber and for each of a plurality of open and available cells: electronically identifying neighboring cells to each of the plurality of open and available cells; electronically determining whether each of the identified neighboring cells are occupied or empty and, if occupied, electronically evaluating a time from load of a specimen container held therein to evaluate a test status of the specimen container held therein, wherein evaluating the test status includes identifying whether the specimen container held therein is in a critical test phase based at least in part on the time from load; then electronically selecting one of the plurality of open and available cells based at least in part on the electronically determining and electronically evaluating; and then electronically directing a loading mechanism (650,700) to electromechanically load the incoming specimen container into the selected one of the plurality of open and available cells, wherein the selecting is carried out to identify the plurality of open and available cells for risk of inducing a false positive in the specimen containers of occupied ones of the identified neighboring cells if loaded with the incoming specimen container. electronically determining and/or obtaining cell availability of cells of a holding structure in an incubated test chamber and for each of a plurality of open and available cells: electronically identifying neighboring cells to each of the plurality of open and available cells; electronically determining whether each of the identified neighboring cells are occupied or empty and, if occupied, electronically evaluating a time from load of a specimen container held therein to evaluate a test status of the specimen container held therein, wherein evaluating the test status includes identifying whether the specimen container held therein is in a critical test phase based at least in part on the time from load; then electronically identifying neighboring cells to each of the plurality of open and available cells; electronically determining whether each of the identified neighboring cells are occupied or empty and, if occupied, electronically evaluating a time from load of a specimen container held therein to evaluate a test status of the specimen container held therein, wherein evaluating the test status includes identifying whether the specimen container held therein is in a critical test phase based at least in part on the time from load; then electronically selecting one of the plurality of open and available cells based at least in part on the electronically determining and electronically evaluating; and then electronically directing a loading mechanism (650,700) to electromechanically load the incoming specimen container into the selected one of the plurality of open and available cells, wherein the selecting is carried out to identify the plurality of open and available cells for risk of inducing a false positive in the specimen containers of occupied ones of the identified neighboring cells if loaded with the incoming specimen container.