Spot tests may be used individually or in combination. The results of a spot tests are typically represented with a short code that includes, in order, (1) a letter indicating the reagent used, (2) a "+" or "−" sign indicating a colour change or lack of colour change, respectively, and (3) a letter or word indicating the colour observed. In addition, care should be taken to indicate which part of the lichen was tested. For example, "Cortex K+ orange, C−, P−" means the cortex of the test specimen turned orange with application of KOH and did not change under bleach or para-phenylenediamine. Similarly, "Medulla K−, KC+R" would indicate the medulla of the lichen was insensitive to application of KOH, but application of KOH followed immediately by bleach caused the medulla to turn red.
