ICD code T60.4X3S – Toxic effect of rodenticides, assault, sequela

Key takeaways

T60.4X3S is a billable ICD-10-CM code for the late effects of a rodenticide poisoning inflicted by another person, after the acute poisoning has resolved.

The 7th character S is required. T60.4 and T60.4X3 are not billable and cannot be submitted on a claim.

Assault must be documented by the provider. With no intent documented, code accidental, and use undetermined only when the record states intent can’t be determined.

Sequence the residual condition first and T60.4X3S after it. Assault external cause codes are optional, added only where payer or state rules ask for them.

Pabau’s claims tools keep diagnosis codes attached to the encounter note, so the record that supports T60.4X3S goes out with the claim.

ICD-10 Code T60.4X3S: Definition and billable status

ICD-10 Code T60.4X3S is a valid, billable ICD-10-CM diagnosis code for FY2026 encounters.

Its official descriptor is “Toxic effect of rodenticides, assault, sequela.” The code sits in Chapter 19 of ICD-10-CM (Injury, poisoning and certain other consequences of external causes, S00-T88). Within it, the code falls under category T60 (Toxic effect of pesticides) and subcategory T60.4 (Toxic effect of rodenticides).

Three elements make this code specific. The substance is a rodenticide, not an organophosphate or a herbicide. The intent is assault, meaning another person inflicted the harm. The encounter is a sequela: the acute poisoning has resolved, and the clinician is managing a residual condition. All three must be documented before the code applies.

Code breakdown: Understanding each character of T60.4X3S

T60.4X3S is a 7-character code. Each position carries a specific meaning, and changing any one character produces a different code with a different intent or encounter type. Knowing the breakdown prevents the most common error: submitting T60.4X3 without the 7th character, which is invalid.

The placeholder X at position 5 is an ICD-10-CM convention. Codes that need a 7th character but have fewer than six characters before it take X as filler. Omitting the X invalidates the code.

What substances does T60.4X3S cover?

Subcategory T60.4 covers rodenticides in general. The anticoagulant rodenticides are the most clinically significant, because they interfere with vitamin K-dependent clotting factors. Superwarfarins cause prolonged coagulopathy that can last weeks to months after a single exposure.

• Superwarfarins (brodifacoum, bromadiolone, difenacoum): long-acting anticoagulants with half-lives measured in weeks, and the most common cause of severe rodenticide coagulopathy
• First-generation coumarins (warfarin-type rodenticides): shorter-acting than superwarfarins. Warfarin prescribed as a drug is coded separately, under the T45.51- series
• Indandiones (diphacinone, chlorophacinone): another anticoagulant class coded under T60.4
• Other rodenticides: non-anticoagulant rodent poisons also fall under T60.4 unless the tabular list sends them elsewhere

Warfarin taken as a medication follows different codes. A poisoning such as an overdose is coded T45.511–T45.514, with intent in the 6th character. An adverse effect of the drug is T45.515.

The deciding factor is the product type: rodenticide formulation versus pharmaceutical. A patient who ate rat bait containing brodifacoum goes to T60.4, while a patient who took too many warfarin tablets goes to T45.51-. When in doubt, check the CDC/NCHS ICD-10-CM web tool for the current tabular entry under T60.4.

Assault vs. accidental vs. self-harm: Choosing the correct intent character

The 6th character encodes intent, following the CMS ICD-10-CM Official Guidelines. Assault (character 3) applies only when the provider documents that another person caused the poisoning. When intent is unknown or unspecified, the guidelines say to code it as accidental (character 1). Undetermined (character 4) is reserved for records that state the intent cannot be determined.

When to use the sequela (S) encounter type

The 7th character S designates a sequela encounter. The original poisoning has resolved, and the patient now has a condition that is a direct consequence of that exposure. That separates it from the initial encounter (A), which covers active treatment, and the subsequent encounter (D), which covers routine care during healing.

A common error on T60.4X3 cases is defaulting to 7th character A for every encounter, wherever the patient is in their care. A patient seen three months after a brodifacoum poisoning, still needing vitamin K for residual coagulopathy, is a sequela encounter. The poisoning itself has resolved, so use S.

• Initial encounter (A): the patient is receiving active treatment for the rodenticide poisoning itself, such as emergency care, antidote therapy, or inpatient coagulation monitoring
• Subsequent encounter (D): active treatment is complete, and the patient returns for routine care while the condition heals
• Sequela (S): the acute poisoning has resolved, and the clinician is treating a residual condition directly caused by it. Examples include persistent coagulopathy, organ damage from bleeding, or ongoing vitamin K deficiency

The two choices work together, as the grid below shows. Intent picks the row, and the encounter type picks the column.

According to the AAPC ICD-10-CM coding guidance, a sequela takes two codes. The residual condition, such as a coagulopathy, is sequenced first. T60.4X3S follows it to show the cause, so it can never be the first-listed code.

Clinical presentation and sequelae of rodenticide assault poisoning

Anticoagulant rodenticides inhibit vitamin K epoxide reductase, which blocks the synthesis of clotting factors II, VII, IX, and X in the liver. Superwarfarins do this far longer than pharmaceutical warfarin. Brodifacoum has a half-life of roughly 16 to 36 days, so patients may need vitamin K therapy for weeks to months after exposure.

Sequelae that justify the S encounter, and must be documented in the record, include:

• Persistent or recurrent coagulopathy (elevated PT/INR that needs ongoing monitoring or treatment)
• Hemorrhagic complications: intracranial bleeding, hemarthrosis, or gastrointestinal hemorrhage
• Organ damage from bleeding episodes during the acute phase
• An ongoing vitamin K deficiency state that needs supplementation
• Anemia caused by significant blood loss during the acute poisoning

Each of these sequelae needs its own ICD-10-CM code, listed first on the claim. T60.4X3S follows it, because the sequela code alone does not describe what is being treated. Coding the residual condition separately is what supports medical necessity.

Companion codes: The residual condition and optional external causes

On a sequela claim, the companion T60.4X3S always needs is the residual condition code. The assault intent already sits in the code’s 6th character. For that reason, the Official Guidelines don’t require a separate assault external cause code with it.

• Residual condition code: the coagulopathy, anemia, or organ damage being treated, sequenced first and followed by T60.4X3S
• Assault external cause codes (X92–Y09): optional. Add one only where a payer or a state reporting rule asks for it
• Perpetrator codes (Y07.-): for confirmed abuse or maltreatment coded with T74.-, not for a poisoning code on its own. Examples include Y07.01 (husband) and Y07.02 (wife), while non-family perpetrators sit under Y07.5-
• Place of occurrence (Y92.-): records where the assault happened. Guidelines report it once, at the initial encounter, so it rarely belongs on a sequela claim

Y07 and Y92 codes have no 7th character, so there is no sequela version of them to match. Check your payer’s rules before adding an external cause code to a sequela claim.

Codes to distinguish: Navigating the T60 family

Category T60 covers toxic effects of pesticides. Several sibling codes get confused with T60.4X3S, either because the substance is similar or because only one character differs.

Documentation requirements for T60.4X3S

Payers reviewing an assault-sequela claim look for a complete documentation chain. A missing link at any point raises a medical necessity question, which can trigger a denial or an additional documentation request (ADR). Claims software for billers that ties the encounter record to the submitted codes makes it harder to send T60.4X3S without its supporting notes.

The medical record must contain all of the following:

• Assault documentation: the provider’s statement that another person inflicted the poisoning. A police report or investigation reference can support it, but ICD-10-CM does not require one
• Substance identification: the rodenticide by name (brodifacoum, bromadiolone, diphacinone) where known. If the record can’t say which type of pesticide was involved, T60.93XS may fit better
• Evidence of sequela: clinical findings showing a late or residual condition, distinct from the acute episode. Coagulopathy labs, records of bleeding events, or ongoing treatment notes all count
• Linkage statement: a provider attestation connecting the current condition to the prior exposure. For example: “patient’s persistent coagulopathy is a sequela of the brodifacoum poisoning event in [month/year]”
• Circumstances of the assault: who was involved and where, if known. This supports an optional external cause code where a payer or state asks for one

Payer requirements and coverage considerations

Prior authorization rules vary by payer and plan, and assault-intent codes can draw a medical necessity review. Following medical billing compliance guidance on assault encounters before submission cuts down these requests.

Key payer considerations for T60.4X3S:

• Medicare/CMS: the ICD-10-CM Official Guidelines apply. Sequela coding is accepted when the acute episode has resolved and the visit treats a residual condition
• Medicaid: state plans vary in how they handle assault-intent codes., so check the applicable state plan
• Commercial payers: most accept sequela coding that follows the Official Guidelines. Assault intent may trigger a medical review request, so make sure the record is complete before submission
• Forensic or legal hold: if records are under subpoena or legal hold, coordinate with compliance and legal before answering payer documentation requests

For practices submitting electronically, a clearinghouse checks the 837P claim file before it reaches the payer. That check catches a missing 7th character or a malformed code as a format-level rejection, before it turns into a denial.

Common claim denial reasons and how to avoid them

T60.4X3S denials cluster around six coding errors, and most are preventable at code selection. Denial management workflows catch them before submission rather than after.

• Submitting the subcategory code T60.4: it is not valid for claim submission. Always use the full 7-character code, T60.4X3S
• Missing 7th character (submitting T60.4X3): T60.4X3 without the S is structurally invalid. Encoders should flag this, but verify before submission
• Using 7th character A when S is correct: a frequent substantive error. If the acute poisoning has resolved and the visit treats a late effect, use S, not A
• Residual condition missing or listed second: T60.4X3S can’t be the first-listed code. The residual condition goes first, and a claim without it has no code to support medical necessity
• Insufficient assault documentation: the assault character needs the provider’s statement that another person caused the poisoning. If intent isn’t documented, query the provider. Without an answer, the guidelines default to accidental (T60.4X1S), not undetermined
• Sequela not linked to the prior event in the record: the provider must explicitly connect the current condition to the resolved poisoning. Without that statement, the payer cannot confirm the sequela relationship

When a T60.4X3S claim comes back denied, check the medical billing denial codes on the ERA to see which element failed. CO-4 points to an inconsistent modifier, and CO-11 means the diagnosis is inconsistent with the procedure. CO-22 means the care may be covered by another payer, which is common when a third party is liable for an assault.

Each code points to a different fix. Before resubmitting, review the clean claim submission requirements for this encounter type.

How Pabau keeps assault-sequela claims tied to the clinical record

A clean T60.4X3S claim depends on notes that often live in different places. The linkage statement sits in the clinical note, the coagulopathy labs sit in results, and the claim goes out from a separate billing tool. When a payer asks for records, someone has to pull them together by hand.

Pabau, the practice management platform we build, keeps the clinical note, the diagnosis codes, and the claim on the same patient record. The coder picks T60.4X3S from the encounter where the provider documented the assault and the residual condition.

So when a payer sends an ADR, the assault statement, the labs, and the linkage note are already in one file. Your billing team answers it from one place instead of chasing three systems.

Document diagnosis codes from the clinical encounter

Pabau links ICD-10 codes like T60.4X3S to the encounter record, so the documentation behind an assault-sequela claim goes out with it. See the workflow from clinical note to clean claim.

Book a demo

Conclusion

On a T60.4X3S claim, most of the work happens before the code is chosen. Confirm that the provider documented the assault, that the acute poisoning has resolved, and that the residual condition is coded and listed first.

If one of those is missing, query the provider rather than assuming. Correcting a guessed intent or encounter type after a denial takes far longer than one query before submission. For the wider view, our guide to revenue cycle management traces how a code like this moves from encounter to payment.

Book a demo to see how Pabau keeps the record behind each assault-sequela claim in one place, ready for the payer.

Continue your research

Need to understand how clearinghouse submission affects ICD-10 claims? Claim.MD clearinghouse overview explains how electronic claim submission handles diagnosis code validation before claims reach the payer.

Want a broader framework for reducing claim rejections? Revenue cycle management guide covers the full workflow from encounter to payment, including where ICD-10 coding errors create the most friction.

Coding a denial-prone case and need to verify the code structure? Superbill documentation guide walks through how to structure the clinical record to support complex diagnosis code combinations at the point of billing.

Frequently asked questions