ICD-10 Code T63.064D: North & South American Snake Venom

Key takeaways

T63.064D reports the toxic effect of venom of another North or South American snake, undetermined intent, at a subsequent encounter.

The word “other” excludes snakes that have a subcategory of their own, so a rattlesnake follow-up is coded T63.014D or T63.011D instead.

The FY2026 Table of Drugs and Chemicals maps copperhead, water moccasin, and fer de lance bites to T63.061 through T63.064.

Undetermined intent is narrow. Use T63.064D only when the record states that intent cannot be determined, and code accidental bites to T63.061D.

T63 codes already carry the external cause, so no W59 code is reported alongside T63.064D at any encounter.

Practice management software like Pabau holds the species, the documented intent, and the encounter stage in one structured record.

ICD-10 Code T63.064D: quick reference

T63.064D reports the toxic effect of venom from a North or South American snake that has no subcategory of its own. In addition, the visit has to be a follow-up, and the record has to state that intent cannot be determined. Break any one of those three conditions, though, and the code is wrong.

The word that causes the most trouble is “other”. For instance, rattlesnake venom has its own subcategory at T63.01, so a rattlesnake follow-up never lands here. By contrast, copperhead, water moccasin, and fer de lance bites do. In short, reading the subcategory title literally is what keeps this code straight.

The descriptor above is the full official wording, taken from the FY2026 tabular list. Indeed, the Centers for Medicare and Medicaid Services (CMS) ICD-10-CM code files list T63.064D as a complete code. The 7th character finishes it, so nothing further is appended.

What does T63.064D mean? Character-by-character breakdown

Every character in T63.064D carries one decision. In fact, reading them in order shows where the two common errors sit. The 5th character fixes the species group, while the 6th fixes the documented intent.

Note where the intent digit sits: it is the 6th character, not the 5th. As a result, coders who count wrong here tend to change the species group when they meant to change the intent. Every position in T63.064D carries meaning, so no placeholder is needed. By comparison, codes that run short of the 7th position take an X instead, as V05.92XS does.

Which snakes does T63.064D cover?

T63.064D covers North and South American snakes that ICD-10-CM does not name in a subcategory of its own. In other words, that is the whole meaning of “other” in the T63.06 title. For example, rattlesnake, coral snake, taipan, and cobra are all named elsewhere, so all four are excluded from T63.06.

The FY2026 tabular list gives T63.06 no inclusion terms at all. Instead, the species mapping lives in the Table of Drugs and Chemicals. Specifically, these are the entries that point to T63.061 through T63.064:

• Copperhead snake (bite) (venom): indexed as a main term in its own right, and the pit viper most often seen in US emergency departments.
• Water moccasin (venom): indexed under the main term Water, subterm moccasin. This is the snake most clinicians call a cottonmouth, Agkistrodon piscivorus.
• Fer de lance (bite) (venom): a Central and South American pit viper of the Bothrops group.
• Snake, American (North) (South) NEC: the catch-all subterm under Venom, venomous, for an American species that is documented but not separately classified.

One wording trap is worth knowing. Specifically, the index term is “water moccasin”, and the synonym “cottonmouth” does not appear as an index entry. Even so, a note that says “cottonmouth bite” still codes to T63.06-, but the coder has to make that connection unaided.

ICD-10-CM classifies snake venom by named species and region, not by taxonomic family. For example, copperheads, cottonmouths, and rattlesnakes are all crotalids, or pit vipers. However, only the first two are coded to T63.06. As a result, thinking at family level is what produces the wrong code.

Region matters most when the species is in doubt. Even so, a bite that happened abroad is still coded from the snake named in the note, and the country narrows which species are plausible. Because of that, it is worth capturing at travel clinic intake alongside the species.

T63.064D vs T63.061D: how intent sets the 6th character

Undetermined intent has to be documented, not assumed. Indeed, the tabular note at the head of the T51-T65 block is explicit: when no intent is indicated, code to accidental. Otherwise, undetermined intent is only for use when the record specifically documents that the intent cannot be determined.

That makes T63.064D the exception rather than the default, since a silent record does not support it. Consequently, most snakebite follow-ups belong to T63.061D, the accidental code. Similarly, the same intent digit runs through the poisoning codes, where T38.802D marks intentional self-harm.

Auditors read T63.064D as a claim worth checking, because the code asserts something the chart has to say out loud. Therefore, if the provider genuinely could not establish intent, that sentence belongs in the note.

T63.064D vs T63.064A vs T63.064S: encounter types explained

Per the ICD-10-CM Official Guidelines for Coding and Reporting, Section I.C.19.a, most chapter 19 categories take three 7th characters. Specifically, T63 takes A, D, and S. By contrast, fracture categories run a much longer menu, which is how a code like S52.692R exists. In short, the character tracks the stage of care, not the number of visits.

Subsequent encounter does not mean second visit. For example, a patient given three days of inpatient antivenom and seen in the office on day ten is at a subsequent encounter. Conversely, a patient readmitted for further active treatment goes back to the A character, even on visit five.

The guidelines also close off a tempting shortcut. Aftercare Z codes are not used for injuries or poisonings where a 7th character already identifies subsequent care. In other words, the D character is the mechanism, so no aftercare code is added beside it.

When to use T63.064D: follow-up scenarios

T63.064D is correct in each scenario below, on three conditions. The species falls in T63.06, the record states that intent cannot be determined, and active treatment has ended. Accordingly, using digital clinical forms built around follow-up visit types puts that check at the point of documentation.

• Wound monitoring visit: the patient returns for assessment of local tissue necrosis, blistering, or wound margins. No further antivenom is given.
• Hematology follow-up: the provider rechecks platelet count, fibrinogen, or PT and INR to track resolution of venom-induced coagulopathy.
• Outpatient antivenom response check: the patient was discharged after initial treatment and returns for serum sickness screening or delayed hypersensitivity review.
• Rehabilitation coordination: referral visits tied to functional recovery after compartment syndrome or tissue loss.
• Telehealth check-in: the provider reviews labs and wound photographs remotely with a patient recovering at home.

Two scenarios do not belong here. First, a visit that restarts active treatment takes the A character. Second, a visit for scarring or permanent nerve damage takes the S character, sequenced after the code for the sequela itself.

Related ICD-10 codes and where T63.064D sits in the hierarchy

T63.064D sits at the bottom of a four-level hierarchy. Therefore, reading the whole T63.0 subcategory roster is the quickest way to see which snakes are carved out of T63.06. Consequently, accurate practice management workflows depend on mapping each species to its correct subcategory.

Within T63.06, the four intent codes are T63.061, T63.062, T63.063, and T63.064, and each takes a 7th character of A, D, or S. As noted earlier, the intent table in this article shows how to choose. Overall, every descriptor here comes from the FY2026 tabular list published by the CDC and NCHS ICD-10-CM browser tool.

Codes commonly confused with T63.064D

• W59.11, bitten by nonvenomous snake: W59 covers nonvenomous reptiles only and carries an Excludes1 note for venomous reptiles. It never appears with a T63.0- code.
• T63.014D, rattlesnake venom, undetermined, subsequent encounter: the correct code for a rattlesnake follow-up, and the one T63.064D is most often used in place of.
• T63.121-, venom of a lizard: a different subcategory entirely, sometimes reached for when the note says reptile rather than snake.

Applicable to, includes, and excludes notes for T63.064D

The tabular notes that govern T63.064D sit above it, at the block and category level. Indeed, T63.06 itself carries none. So, anything a commercial lookup shows as an Applicable To list for this code comes from elsewhere. Specifically, the source is the index or the approximate synonym files, not the tabular list.

• Includes, at T63: bite or touch of venomous animal, and pricked or stuck by thorn or leaf.
• Excludes2, at T63: ingestion of a toxic animal or plant, which is coded to T61.- or T62.-. In other words, an Excludes2 note means both codes may be reported together when both happened.
• Excludes1, at the T51-T65 block: contact with and suspected exposure to toxic substances, coded to Z77.-. As a result, that code cannot be reported with T63.064D.
• Excludes1, at W59: contact with venomous reptile, covering T63.0- and T63.1-. Consequently, this is the note that rules out pairing T63.064D with a W59 external cause code.
• Use additional code, at the T51-T65 block: report every associated manifestation of the toxic effect. Add a retained foreign body code from Z18.- if one applies.

Coding guidelines and documentation requirements

Sequence T63.064D first, then code the manifestations being treated at that visit. This order comes directly from Section I.C.19.e.5.(d), Toxic Effects, of the Official Guidelines. Accordingly, using claims management software that handles multi-code claims keeps the sequence intact on submission.

• Do not add an external cause code. Codes in T36 to T65 are combination codes that already carry the intent, so the guidelines require no chapter 20 cause code alongside them.
• Never report W59.1- with T63.064D. In fact, the Excludes1 note at W59 bars it, and the pairing is a visible contradiction on the claim.
• Code every manifestation you treated: cellulitis, coagulopathy, tissue necrosis, or compartment syndrome each get their own code, sequenced after T63.064D.
• Place of occurrence (Y92.-) belongs at the initial encounter only. It is assigned once, and Y92.9 is not used when the place is unstated.
• Activity codes are Y93.-, not Y92.-. The two categories are routinely confused, and neither is re-reported at a follow-up visit.
• Skip the aftercare Z code. The D character already identifies subsequent care.

The note itself has to support all three parts of the code. Fortunately, structured medical documentation workflows make that easier than reconstructing it from free text later.

• Species, in plain words: copperhead, water moccasin, or fer de lance, or a clear statement that the snake was not identified.
• Intent: an explicit statement that intent cannot be determined, since that is the only support for the 6th character 4.
• Care stage: confirmation that active treatment has ended and the visit is routine recovery care.
• Current findings: the manifestations assessed at this visit, which justify both the encounter and any additional codes.

The structured clinical record in a practice management platform lets a provider flag the care stage at each visit. As a result, billing works from a recorded answer rather than an inference.

Code history and FY2027 validity

T63.064D has been billable since ICD-10-CM took effect on October 1, 2015. In fact, its long descriptor in the FY2016 code file is word for word the descriptor in FY2026. Overall, the code has not been revised, split, or retired in that time.

It also survives the next annual update. The FY2027 code descriptions file, effective October 1, 2026, carries T63.064D with the same wording. Likewise, the same holds for its neighbors T63.061D and T63.014D, so none of the distinctions in this article change on that date.

The AAPC ICD-10-CM code range reference is useful for a quick lookup. However, always verify anything you bill against the current fiscal year file from CMS or NCHS, because those two are the source of record.

How Pabau supports accurate envenomation follow-up coding

A practice tracking snakebite recoveries usually holds the three facts a coder needs in three different places. Specifically, species sits in the emergency department note, intent sits in a narrative paragraph, and the care stage is inferred from the visit date.

Most of these follow-ups happen back in primary care, away from the team that gave the antivenom. As a result, coders then rebuild the story from notes written for another purpose.

Practice management software like Pabau turns those three into recorded fields. Specifically, custom follow-up forms ask for the species and the care stage at intake, and HIPAA-compliant clinical documentation keeps them attached to the visit. As a result, the coder opens one record and reads the answers.

Billing works from the same record. Pabau’s claims management features assemble the diagnosis codes recorded at the visit into a single claim. Additionally, the same tools track what the payer does with it, so the clinical team decides the codes while the software carries them.

The outcome is fewer follow-up claims returned for a code that contradicts the note. Notably, this matters most on low-volume codes like T63.064D, where nobody in the practice has built up muscle memory.

Simplify follow-up encounter coding with Pabau

Pabau records the encounter stage at intake, assembles multi-code claims, and keeps snakebite follow-up documentation in one place. See how it works for your practice.

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Conclusion

T63.064D is a precise code, and its precision is what trips people up. Specifically, it applies to a North or South American snake with no subcategory of its own. In addition, the visit must fall after active treatment has ended, and the record must state that intent cannot be determined. For example, a rattlesnake bite fails the first test and belongs in T63.01-.

First, check the species against the Table of Drugs and Chemicals, check the note for an explicit statement about intent, and confirm active treatment has finished. Then add the manifestation codes, leave the external cause codes off, and the claim holds up.

If your team is rebuilding those three facts from narrative notes at every follow-up, the documentation is the problem rather than the code. Book a demo to see how Pabau captures species, intent, and care stage at intake.

Continue your research

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