There are two standards governing the amount of protection provided by cut resistant gloves and a recent change is attempting to get the two standards more closely aligned.
The ANSI/ISEA 105-11, also known as ASTM1790, is an American standard while the EN388 is the standard for the rest of the world. The EN388 standard is often referenced in the United States as well because it also incorporates testing categories for abrasion, puncture, and tear that are not part of the ASNI standard and will also now include impact hazard testing.
There are three primary reasons for the changes to the standard. First, the levels did not match well between the two standards. As an example, ANSI cut level 2 starts at 500 grams of weight while 500 grams of weight was the start of cut level 3 under the old EN388 standard. With the changes to the standards the levels between the two will be more consistent and both now represent 500 grams of weight.
Second, the two tests used totally different protocols for determining cut resistance. A common misconception in the past was that if ANSI cut level 2 started at 500 grams of weight and EN388 cut level 3 started at 500 grams of weight that an EN388 cut level 3 glove would offer the same protection as an ANSI cut level 2 glove but because of different testing methods that was not true. One major difference is that the ANSI test used a new blade for each of the 10 tests required during testing while the EN388 standard used the same blade resulting in skewed protection numbers as the blade became dull. The Coupe test used during EN388 testing was found to be unreliable and will be phased out over the next few years and both standards will use the new ISO13997 TDM test.
Lastly, ANSI cut level 4 had a very broad range. In the old standard it started at 1500 grams of weight and topped out at 3499 grams. This meant it was difficult for users to compare gloves since two gloves could claim cut level 4 protection while one might be barely past the 1500 gram threshold and the other could be approaching the upper limit of 3500 grams. To adjust this issue cut level 4 will now range from 1500-2199 grams of weight and additional levels have been added.
In the new ANSI standard there will no longer be five levels of protection but there will now be nine levels and will now be designated as A1, A2, etc., to reflect the new standard. In the EN388 standard they will change from five levels to six designated as A-F and will no longer use a numerical designation.