EN 388:2016 prints two different cut-resistance results on the same glove pictogram because it runs two different cut tests, and the two values are not interchangeable [S1][S2].
The first is the legacy Coup Test index, shown as a number from 1 to 5 (the second digit of the four-digit mechanical code, e.g. 4.X.X.X). The second is the ISO 13997 TDM-100 result, shown as a letter A through F, with a force range of roughly 2 N to 30 N (200-3000 g) [S3][S4].
What the Coup Test Number Actually Measures
The Coup Test presses a rotating circular blade against the glove sample under a fixed 5 N load and counts blade rotations to cut-through, then indexes that count against a control fabric [S3][S7]. EN 388 bins the ratio into five levels: index 1 (~1.2), 2 (2.5), 3 (5.0), 4 (10.0), and 5 (20.0), where higher means more rotations before cut-through [S5].
The method is fast and cheap, but the circular blade dulls quickly on high-performance fibres such as HPPE, aramid, or steel-core knit, so the recorded drop-off in cutting efficiency gets attributed to the glove rather than the blade [S3][S8].
Why EN 388:2016 Added the ISO 13997 TDM Letter
EN 388:2016 keeps the Coup Test but adds ISO 13997, also called the TDM-100 test, to handle materials that the Coup blade cannot resolve [S1][S2][S7][S8].
The TDM-100 pushes a fresh straight blade across a 20 mm cut path on each cycle, ramps the normal force in Newtons, and records the force at cut-through; that Newton value is mapped to letters A through F: A 2 N, B 5 N, C 10 N, D 15 N, E 22 N, F 30 N [S3][S4].
Because every cut uses a new blade segment, dulling is no longer the limiting factor, which is why any glove with a credible high-cut claim is rated with the TDM letter rather than the Coup number [S3][S8].
Reading the Pictogram: Where the Two Values Sit
On the EN 388 shield the mechanical hazards are listed in this fixed order: a) abrasion, b) cut, c) tear, d) puncture, with an optional e) ISO 13997 cut letter placed at the right of the shield [S1][S6].
If a glove dulls the Coup blade before cut-through, or is otherwise unsuitable for the rotating-blade method, EN 388:2016 allows the Coup digit to be replaced by the letter X, and the ISO 13997 TDM letter becomes the only usable cut-resistance figure on the label [S1][S8].
For a four-digit EN 388 string like 4.5.4.4.C, that means abrasion level 4, Coup cut level 5, tear level 4, puncture level 4, and a TDM-100 cut result of letter C, which corresponds to a cut-through force near 10 N [S6].
Decision Matrix: Which Value to Trust on the Job
For light assembly, packaging, and warehouse handling where the cut hazard is mostly cardboard and film, a Coup Test number 1-3 is normally sufficient and the TDM letter is informational [S3][S5].
For sheet-metal work, glass and metal handling, blade changeover on converting lines, and any task involving coated HPPE, aramid, or steel-fibre liners, the TDM letter A-F is the only defensible cut spec; buyers should anchor on the Newton value behind the letter (C = 10 N, D = 15 N, E = 22 N, F = 30 N) rather than the letter itself [S3][S4][S7].
If the printed string is X.X.X.X or X in the cut position, the TDM letter next to the shield is mandatory, and any specification that still quotes a Coup number for that glove is wrong by the EN 388:2016 rules [S1][S8].
Comparison vs ANSI/ISEA 105: Why the Letter Scales Look Familiar
ANSI/ISEA 105-2016 (U.S.) runs the ASTM F2992-15 TDM-100 test and reports cut resistance on an A1-A9 scale from 200 g to 6000 g (2 N to 60 N) [S3].
EN 388:2016 runs the closely related ISO 13997 TDM-100 test and reports on an A-F scale from 2 N to 30 N (200-3000 g); the test mechanics (new straight blade per cut, ramped force, 20 mm cut path) are the same family [S3][S4].
The practical difference is range: EN 388 caps at F (30 N) because the European regulation focused on industrial hand protection, while ANSI/ISEA extends to A9 (60 N) for higher-risk tasks like heavy sheet metal and certain cut-and-shear applications [S3].
Common Specification Mistakes and Failure Modes
Specifying "EN 388 cut level 5" alone is ambiguous under EN 388:2016, because it could mean Coup 5 (a ratio index of 20.0) or TDM letter E (22 N) depending on how the supplier reads the standard; the unambiguous spec is the full shield string plus the TDM letter [S1][S6].
A second failure mode is treating a Coup result of 1 or 2 as disqualifying when the TDM letter is D, E, or F, which on coated HPPE and stainless-steel-core knit is common; the Coup number is depressed by blade dulling, not by the glove's true cut resistance [S3][S8].
For procurement, the minimum auditable spec for any cut-resistant safety glove under EN 388:2016 is the four-digit mechanical code together with the ISO 13997 letter (or X) printed alongside the shield, sourced from a current CE declaration of conformity, not from a marketing sheet.
Next signal to watch: the next EN 388 maintenance cycle and any move to align the TDM-100 force table with ANSI/ISEA 105-2024 cut levels, which would let buyers quote one Newton value across both the European and U.S. PPE supply chains.
Spec-level background on the components involved: electronic test, and measurement test.
For related coverage, see HSLA vs Q&T Alloy Plate: Spec-Driven Selection for Structural and Heavy Equipment.