| S20.321 | Blister (nonthermal) of right front wall of thorax | NON-BILLABLE CODE |
| S20.321A | Blister (nonthermal) of right front wall of thorax, initial encounter | BILLABLE CODE |
| S20.321D | Blister (nonthermal) of right front wall of thorax, subsequent encounter | BILLABLE CODE |
| S20.321S | Blister (nonthermal) of right front wall of thorax, sequela | BILLABLE CODE |
| S20.322 | Blister (nonthermal) of left front wall of thorax | NON-BILLABLE CODE |
| S20.322A | Blister (nonthermal) of left front wall of thorax, initial encounter | BILLABLE CODE |
| S20.322D | Blister (nonthermal) of left front wall of thorax, subsequent encounter | BILLABLE CODE |
| S20.322S | Blister (nonthermal) of left front wall of thorax, sequela | BILLABLE CODE |
| S20.323 | Blister (nonthermal) of bilateral front wall of thorax | NON-BILLABLE CODE |
| S20.323A | Blister (nonthermal) of bilateral front wall of thorax, initial encounter | BILLABLE CODE |
| S20.323D | Blister (nonthermal) of bilateral front wall of thorax, subsequent encounter | BILLABLE CODE |
| S20.323S | Blister (nonthermal) of bilateral front wall of thorax, sequela | BILLABLE CODE |
| S20.324 | Blister (nonthermal) of middle front wall of thorax | NON-BILLABLE CODE |
| S20.324A | Blister (nonthermal) of middle front wall of thorax, initial encounter | BILLABLE CODE |
| S20.324D | Blister (nonthermal) of middle front wall of thorax, subsequent encounter | BILLABLE CODE |
| S20.324S | Blister (nonthermal) of middle front wall of thorax, sequela | BILLABLE CODE |
| S20.329 | Blister (nonthermal) of unspecified front wall of thorax | NON-BILLABLE CODE |
| S20.329A | Blister (nonthermal) of unspecified front wall of thorax, initial encounter | BILLABLE CODE |
| S20.329D | Blister (nonthermal) of unspecified front wall of thorax, subsequent encounter | BILLABLE CODE |
| S20.329S | Blister (nonthermal) of unspecified front wall of thorax, sequela | BILLABLE CODE |
