What will be suitable surfacer area for Swab?

Dear All
For Swab of residue what will be the suitable surface Area.
25cm^2 is enough or 100cm^2 to be taken.

in criterian limit is it affect?

Dear Mr Nimesh,

There is no guideline stating the requirement regarding the selection of surface area for swab samples. It is common practice in industry to use 25 sq. cm or 100 sq. cm for swab sampling. It is not necessary that each and everytime one has to comply with the requirement of 25 sq. cm or 100 sq. cm swab sample area. Sometime it happens that one has to deviate from the requirement because the equipment (or its part) geometry doesn’t allow to sample a full 25 sq. cm or 100 sq. cm sample area. For example, collecting swab sample from a die or punch of a tabletting machine (in this case it is not possible to swab a 25 sq. cm or 100 sq. cm sample area). If the accessibility of the equipment part allows then we try to swab 25 sq. cm or 100 sq. cm sample area, otherwise we may use lesser or greater surface area for the collection of swab sample. Selecting different surface areas for swab sampling doesn’t affect the CV limits.