What is the pitting edema scale?

The pitting edema scale is a tool used to assess the severity of a patient's edema, according to Progressive Health. Using the scale, edema is graded from 1+ to 4+, with 4+ being severe edema.

Progressive Health states that when pressure is applied to 1+ edema, a pit of 2 millimeters or less is created, which disappears immediately. Grade 2+ edema pits from 2 to 4 millimeters and disappears in 10 to 15 seconds. Edema that pits between 4 and 6 millimeters and disappears in one minute is graded 3+ edema. Grade 4+ edema indents between 6 and 8 millimeters and lasts for two to five minutes.