W59.11XD Bitten by nonvenomous snake, subsequent encounter

ICD-10-CM Code W59.11XD: Bitten by nonvenomous snake, subsequent encounter

ICD-10-CM code W59.11XD is identified in Medicare documentation as "Bitten by nonvenomous snake, subsequent encounter." Clinical literature indicates that 70 percent of all snakebites are inflicted by nonvenomous snakes. This hybrid reference synthesizes official coding listings with clinical context regarding nonvenomous snakebites. 6 3

What this code represents

A Centers for Medicare & Medicaid Services document lists W59.11XD with the official label "Bitten by nonvenomous snake, subsequent encounter." The same document also lists W59.11XA as "Bitten by nonvenomous snake, initial encounter." 6

The Centers for Medicare & Medicaid Services document places W59.11XD among a sequence of subsequent encounter codes for animal bites, including W59.01XD for nonvenomous lizards and W59.81XD for other nonvenomous reptiles. This listing groups nonvenomous reptile bites together. 6

Plain-language overview

Clinical literature states that 70 percent of all snakebites are by nonvenomous snakes. The same literature advises reassuring the victim based on this 70 percent figure and the fact that 50 percent of bites by venomous species are dry bites. 3

Clinical context

Clinical literature notes that some people who are bitten by snakes may develop striking symptoms and signs even when no venom has been injected. Additionally, fang marks do not confirm a snakebite because bites by lizards, rodents, and some insects also leave paired punctures. 3 1

Clinical literature indicates that identifying the biting species helps avoid unnecessary antivenom in patients bitten by non-venomous snakes. However, identification of snakes based on description by victims or recognition from pictures is often unreliable. 1

What the sources add

The Centers for Medicare & Medicaid Services source provides the specific alphanumeric code W59.11XD and its label, while the clinical literature from PMC provides the statistic that 70 percent of snakebites are by nonvenomous snakes. Together, these sources link the billing code to clinical literature on nonvenomous bites. 6 3

Coverage and utilization context

The Centers for Medicare & Medicaid Services document includes W59.11XD within a Medicare Secondary Payer manual. The presence of this code in the manual establishes its existence in Medicare administrative references, but does not confirm payer-specific coverage. 6

Documentation considerations

Clinical literature states that it is essential to establish that a victim has been bitten by a snake and not by some other animal. This can be cross-checked by looking for fang marks and signs of local envenomation. 3

Sources

1. Managing snakebite — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
2. Venomous Snakes: A Neglected Hazard for Outdoor Workers — cdc.gov; accessed 2026-07-25.
3. Emergency treatment of a snake bite: Pearls from literature — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
4. Snake bites: MedlinePlus Medical Encyclopedia — medlineplus.gov; accessed 2026-07-25.
5. Venomous Snakes at Work — cdc.gov; accessed 2026-07-25.
6. Pub 100-05 Medicare Secondary Payer — cms.gov; accessed 2026-07-25.