T70.3XXA (Caisson disease [decompression sickness], initial encounter) compared with T70.3XXD (Caisson disease [decompression sickness], subsequent encounter), from the official CMS tabular data. T70.3XXA and T70.3XXD code the same injury at a different phase of treatment. MedCoder-derived
Same underlying diagnosis, different encounter phase.
The 7th character records the phase of care for the encounter being coded, so a single encounter takes one of these characters, not several. Review whether both phases belong on the same episode of care.
Source: ICD-10-CM Official Guidelines, Section I.C.19.a
Same injury, other encounter phase. T70.3XXA and T70.3XXD code the same injury at a different phase of treatment, set by the 7th character.
The 7th character records the type of care given at the encounter being coded (ICD-10-CM Official Guidelines, Section I.C.19.a), so one encounter takes one of these, not both.
| T70.3XXACaisson disease [decompression sickness], initial encounter | T70.3XXDCaisson disease [decompression sickness], subsequent encounter | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | S00-T88 — Injury, poisoning and certain other consequences of external causes | S00-T88 — Injury, poisoning and certain other consequences of external causes |
| Definition | Caisson disease [decompression sickness], initial encounter is a billable ICD-10-CM diagnosis code (T70.3A). | Caisson disease [decompression sickness], subsequent encounter is a billable ICD-10-CM diagnosis code (T70.3D). |
| 7th character | The appropriate 7th character is to be added to each code from category T70 | The appropriate 7th character is to be added to each code from category T70 |
| Includes | Compressed-air disease Diver's palsy or paralysis | Compressed-air disease Diver's palsy or paralysis |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources