Assessing clarity and erasability of commercially available pens for surgical site marking: a comparative study in human volunteers

Table 1 Represents the modelled grayscale data for marks made on both upper and lower limbs, the variability of the marks and the effect of surgical prep on each mark

Pen	Mark	Mark arm SD	Mark leg SD	Prep (+/−SD)
A	0.684	0.065	0.038	0.278 +/−0.082
B	0.595	0.057	0.033	0.417 +/−0.123
C	0.519	0.049	0.029	0.418 +/−0.124
D	0.649	0.062	0.036	0.005 +/−0.001
E	0.675	0.064	0.038	0.213+/−0.063
F	0.683	0.065	0.038	0.277 +/−0.082
G	0.620	0.059	0.034	0.421 +/−0.125
H	0.411	0.039	0.023	0.481 +/−0.142

The data model standardises the value for the initial mark (Mark) and the effect of skin preparation (Prep) so that they are the same for both the upper and lower limbs. In the column headed “Mark” a value of 0 indicates no discernible mark and a value of 1 indicates a completely black mark. In the column headed “Prep (±SD)” a value of 0 represents no effect of surgical preparation, and a value of 1 represents complete removal of the mark by surgical prep. The columns headed “Mark Arm SD” and Mark Leg SD” represent the variability of clarity of the marks made on upper and lower limbs

ISSN: 1754-9493