The ornamental design for a diagnostic apparatus for medical or laboratory use, as shown and described.
Figure 1.1 is a perspective view of a diagnostic apparatus for medical or laboratory use;
Figure 1.2 is another perspective view thereof;
Figure 1.3 is a front view thereof;
Figure 1.4 is a rear view thereof;
Figure 1.5 is a top view thereof;
Figure 1.6 is a hoiiorn view thereof;
Figure 1.7 is a side view thereof; and
Figure 1.8 is another side view thereof.
The broken lines and broken line areas shown in Figures 1.1-1.8 illustrate portions of the diagnostic apparatus for medical or laboratory use that form no part of the claimed design.