You should always use a larger (i.e., 1000 μL) pipette to accurately transfer the required volume of saliva specimen. Smaller pipettes such as 100 or 200 μL pipettes have a smaller tapered tip that make it difficult to accurately pipette viscous liquids such as saliva.
While using a larger pipette will usually work, some saliva specimens can be especially viscous. If you find that a 1000 μL pipette is still insufficient for transferring the correct volume, you can cut off part of the end of the tapered pipette tip using a sterile pair of scissors or razor. This will make the pipette tip opening wider, allowing the full volume to be more easily transferred.
Ensure that all saliva specimens are homogenized prior to pipetting by vortexing or pipetting up and down.