Just because a surface looks clean, it does not mean it is clean. Microorganisms, biofilm and other biological residues are not visible to the unaided eye. Testing the surface ATP is an effect marker for the hygienic status of any environment.
A benchmark for hospitals for RLU levels:
Pass – Less than 100 RLU
Caution – 100 – 200 RLU
Fail – Greater than 201 RLU
Once the area has been treated with UVC, the levels will be below 100 RLU rendering it sterile. A report is produced on specialist software giving before and after levels. A completion certificate is produced also to keep with your health and safety records.