| Surface/equipment | Number of alleles detected | 
      
        | RFU≥100 | RFU≥50 | 
      
        | Drawer of    laboratory cupboard (outside surface) | 10 | 17 | 
      
        | Laboratory    bench | 12 | 19 | 
      
        | Centrifuge    used for reference samples (outside surface) | 1 | 5 | 
      
        | Centrifuge    used for evidence samples (outside surface) | 1 | 1 | 
      
        | Container    with autoclaved tubes (outside surface) | 0 | 1 | 
      
        | Pipetholder    in laminar flow cabinet | 0 | 1 | 
      
        | On/off    button laminar flow cabinet | 7 | 9 | 
      
        | Container    with autoclaved filtertips | 0 | 0 | 
      
        | Handle    laboratory freezer | 7 | 13 | 
      
        | Handle    laboratory fridge | 2 | 7 | 
      
        | Box    containing centrifugal filter devices (outside surface) | 1 | 5 | 
      
        | Rack for    tubes (empty) | 14 | 18 | 
      
        | Vortex | 3 | 7 | 
      
        | Electronic    pipette | 5 | 10 | 
      
        | Outside laminar    flow cabinet (front side) | 0 | 0 | 
      
        | Inside laminar    flow cabinet (bottom) | 0 | 0 | 
      
        | Inside    pipetting liquid handler with UV lamp (left side) | 0 | 0 | 
      
        | Inside    pipetting liquid handler with UV lamp (right side) | 0 | 0 | 
      
        | Inside    pipetting liquid handler with UV lamp (bottom) | 0 | 0 |