The phrase 'indicate positive' is correct and usable in written English
You could use it in a sentence such as, "The results of the test indicated positive."
Index readings higher than 50 indicate positive sentiment about the market.
Research is currently under way in Spain, and preliminary reports indicate positive effects with this population.
Brown stained cells indicate positive signal.
Red arrow heads indicate positive bands detected by sera.
Arrow and blocked lines indicate positive and negative regulation, respectively.
Straight and dotted lines indicate positive and negative effects, respectively.
The results indicate positive correlation between SCB test results and other independent fatigue tests.
Statistical analyses indicate positive correlation among most of the chemical parameters.
Right and left oblique ellipses indicate positive and negative correlations, respectively.
Solid symbols indicate positive inclination, and empty symbols negative inclination of natural remanent magnetization.
Numbers indicate positive and negative V D median values in each of the shown time intervals.
