The ornamental design for a samplecassette for a diagnostic instrument, as shown and described.
FIG. 1 is a left rear perspective view of a sample cassette for a diagnostic instrument showing our new design, where the top portion is optically opaque and the bottom portion is optically transparent;
FIG. 2 is a left front perspective view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a rear view thereof;
FIG. 7 is a front view thereof;
FIG. 8 is a right rear perspective view thereof; and,
FIG. 9 is a right front perspective view thereof.
The bottom view is plain and unornamented and is not part of the claimed design. The broken lines of uneven length define the boundary of the claimed design.