FIG. 1.

Schematic diagrams of three pooled testing strategies considered: D2, D3, and A2m. Positive pools are in gray; positive specimens are in black. In D2 (a), a positive master pool is broken down into individual specimens. One or more of these specimens may be positive. In D3 (b), a positive master pool is broken down into multiple subpools, all of which are tested. Positive subpools are broken into individual specimens, and one or more of these specimens may be positive. In A2m (c), if a master pool is positive, row and column pools are tested, some of which may be positive. Specimens at the intersection of positive row and column pools are tested individually; some or all of these may be positive.