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ICD-10/T50.916A

T50.916A ICD-10-CM Code: Underdosing of multiple unspecified drugs, medicaments and biological substances, initial encounter

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

  • MS-DRG 951 — OTHER FACTORS INFLUENCING HEALTH STATUS (MDC 23)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Official Registry Overview & Definition

Underdosing of multiple unspecified drugs, medicaments and biological substances, initial encounter is a billable ICD-10-CM diagnosis code (T50.916A).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for T50.916A in the official ICD-10-CM tabular list.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • adverse effect of correct substance properly administered
  • poisoning by overdose of substance
  • poisoning by wrong substance given or taken in error
  • underdosing by (inadvertently) (deliberately) taking less substance than prescribed or instructed

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Code First

Underlying conditions that must be sequenced before this code.

  • Code first, for adverse effects, the nature of the adverse effect, such as:
  • adverse effect NOS (T88.7)
  • aspirin gastritis (K29.-)
  • blood disorders (D56-D76)
  • contact dermatitis (L23-L25)
  • dermatitis due to substances taken internally (L27.-)
  • nephropathy (N14.0-N14.2)

Code Also

Additional codes that may be required to fully describe the encounter.

  • any specific drugs, medicaments and biological substances

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code(s) to specify:
  • manifestations of poisoning
  • underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
  • underdosing of medication regimen (Z91.12-, Z91.13-)

Change history

  • FY2020 — 2019-10-01
    Added to the code set
    Underdosing of multiple unspecified drugs, medicaments and biological substances, initial encounter
    FY2020 changes

Verify Before Coding

  • Billable — reportable as written.
  • Principal-diagnosis restriction. The Medicare Code Editor lists this code as unacceptable as a principal diagnosis: it describes a circumstance influencing health status rather than a current illness or injury being treated. It is valid as a secondary diagnosis.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim.

Contextual Map

Every relationship of T50.916A in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

  • S00-T88 — Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) (S00-T88) [Hierarchy]
  • T36-T50 — Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances [Hierarchy]
  • T47-T50 — Hormones & Systemic Agents [Hierarchy]

Referenced by Excludes1 notes

  • T38 — Poisoning by, adverse effect of and underdosing of hormones and their synthetic substitutes and antagonists, not elsewhere classified [Excludes1](via T50.9.-): “parathyroid hormones and derivatives (T50.9-)”

Referenced by Use Additional Code instructions

  • G61.1 — Serum neuropathy [Use Additional Code](via T50.-): “code for adverse effect, if applicable, to identify serum (T50.-)”

Clinical classification (CCSR)

  • INJ029 — Underdosing of drugs and medicaments, initial encounter [CCSR]

Potential MS-DRG

  • DRG 951 — OTHER FACTORS INFLUENCING HEALTH STATUS [MS-DRG]: “OTHER FACTORS INFLUENCING HEALTH STATUS (MDC 23)”

MDC crossing · procedures (1235)

  • MDC 23 — Factors Influencing Health Status and Other Contacts with Health Services [MDC crossing]: “Factors Influencing Health Status and Other Contacts with Health Services — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs.”
  • F003GKZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Audiovisual Equipment [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Audiovisual Equipment — grouped in MDC 23, the procedure side of this code's crossing.”
  • F003GMZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Augmentative / Alternative Communication Equipment [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Augmentative / Alternative Communication Equipment — grouped in MDC 23, the procedure side of this code's crossing.”
  • F003GPZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Computer [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Computer — grouped in MDC 23, the procedure side of this code's crossing.”
  • F003GYZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Other Equipment [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body using Other Equipment — grouped in MDC 23, the procedure side of this code's crossing.”
  • F003GZZ — Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body [Same-MDC procedure]: “Communicative/Cognitive Integration Skills Assessment of Neurological System - Whole Body — grouped in MDC 23, the procedure side of this code's crossing.”
  • and 1230 more

Drugs & chemicals

  • Multiple unspecified drugs, medicaments and biological substances — Multiple unspecified drugs, medicaments and biological substances — Underdosing [Drug table]: “Multiple unspecified drugs, medicaments and biological substances (Underdosing)”

Nearest codes (40)

  • T50 — Poisoning by, adverse effect of and underdosing of diuretics and other and unspecified drugs, medicaments and biological substances [Sibling]
  • T50.911A — Poisoning by multiple unspecified drugs, medicaments and biological substances, accidental (unintentional), initial encounter [Sibling]
  • T50.911D — Poisoning by multiple unspecified drugs, medicaments and biological substances, accidental (unintentional), subsequent encounter [Sibling]
  • T50.911S — Poisoning by multiple unspecified drugs, medicaments and biological substances, accidental (unintentional), sequela [Sibling]
  • T50.912 — Poisoning by multiple unspecified drugs, medicaments and biological substances, intentional self-harm [Sibling]
  • T50.912A — Poisoning by multiple unspecified drugs, medicaments and biological substances, intentional self-harm, initial encounter [Sibling]
  • T50.912D — Poisoning by multiple unspecified drugs, medicaments and biological substances, intentional self-harm, subsequent encounter [Sibling]
  • T50.912S — Poisoning by multiple unspecified drugs, medicaments and biological substances, intentional self-harm, sequela [Sibling]
  • and 32 more

Change history

  • FY2020 — Added to the code set [Change history]

Referenced by Other Codes

Clinical classification (AHRQ CCSR):INJ029 — Underdosing of drugs and medicaments, initial encounter.

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Potential MS-DRG Relationships (FY2026)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Named in the grouper logic of 1 MS-DRG: DRG 951 (MDC 23).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Official ICD-10-CM tabular notes on other codes that name T50.916A or its code family.

1 Excludes1 notes: T38 (via T50.9.-).

1 Use Additional Code instructions: G61.1 (via T50.-).

Frequently Asked Questions (FAQ) & Clinical Guidance

Does T50.916A require a 7th character?

Yes. The appropriate 7th character is to be added to each code from category T50.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T50.916A in its code family, with their registry titles.

  • T50.915 — Adverse effect of multiple unspecified drugs, medicaments and biological substances
  • T50.915A — Adverse effect of multiple unspecified drugs, medicaments and biological substances, initial encounter
  • T50.915D — Adverse effect of multiple unspecified drugs, medicaments and biological substances, subsequent encounter
  • T50.915S — Adverse effect of multiple unspecified drugs, medicaments and biological substances, sequela
  • T50.916 — Underdosing of multiple unspecified drugs, medicaments and biological substances
  • T50.916D — Underdosing of multiple unspecified drugs, medicaments and biological substances, subsequent encounter
  • T50.916S — Underdosing of multiple unspecified drugs, medicaments and biological substances, sequela
  • T50.99 — Poisoning by, adverse effect of and underdosing of other drugs, medicaments and biological substances
  • T50.991 — Poisoning by other drugs, medicaments and biological substances, accidental (unintentional)
  • T50.991A — Poisoning by other drugs, medicaments and biological substances, accidental (unintentional), initial encounter

View all codes in the T50 family

Associated Substances (1)

Substances from the official ICD-10-CM Table of Drugs and Chemicals that map to this code.

  • Multiple unspecified drugs, medicaments and biological substances