Guidelines for Patent Examination, Part Ⅱ, Chapter 2, Section 3.2.2 prescribes: generally, such terms as “about”, “approximately”, “etc.”, “or the like” and the like shall not be used in a claim, since they are likely to make the protection extent of the claim unclear. Therefore, in most cases, the Examiner generally requires the Applicant to delete the word “about” from the claims.  

However, Guidelines for Patent Examination further indicates in the above section, where in a claim there exists such a term, the examiner shall make a judgment as to whether use of such term makes the claim unclear according to the specific situation, and if not, the use of such term is permitted. That is to say, the term “about” is not necessary to be deleted from the claims in some situations.

In one case of our client, the Examiner asked the Applicant to delete the word “about” from the claims.  For this case, we noted the specification clearly records the definition on the term “about”: As used herein, the term “about” means plus or minus 10% of the numerical value of the number with which it is being used.   Moreover, we learned from our client, the content of one ingredient in the final commercial product is not directly recorded in the specification and not fall within the range directly recorded in the specification. By our calculation, we found, one particular content value of this ingredient recorded in the specification plus 10% exactly covers the content of this ingredient in the final commercial product.  

In view of these, we further incorporate the above definition on the term “about” into the claims, and argued, in combination with said definition and by simple calculation, the scope of the claim is clear for the skilled in the art, and thus the term “about” can be kept in the claims.  Finally, the Examiner accepted our amendments and arguments.

In summary, when drafting one patent application relating to a value, a unit, a constant, or a range of values, we suggest the Applicant incorporating the definition on the term “about” according to the particular technical solution in the specification.  Such definition may be drafted as above or “ ‘about x’ includes and describes ‘x’ per se. In some embodiments, the term ‘about’ when used in association with a measurement, or used to modify a value, a unit, a constant, or a range of values, refers to variations of +/- 2% of the stated value or parameter.”