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Not otherwise specified

"Not otherwise specified (NOS) is a diagnostic category employed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), to denote mental disorders that display symptoms aligning with a broader diagnostic class but fail to satisfy the complete criteria for any defined disorder within that class." This residual category allowed clinicians to acknowledge clinically significant presentations that did not fit neatly into established subtypes, facilitating diagnosis in cases with atypical or insufficient information.^[1] Introduced in earlier DSM editions and prominently featured in DSM-IV (published in 1994) and its text revision (DSM-IV-TR in 2000), NOS was applied across various psychiatric domains, including mood, anxiety, psychotic, and pervasive developmental disorders.^[2] In DSM-IV, examples of NOS usage included Psychotic Disorder NOS, which encompassed delusions, hallucinations, disorganized speech, or grossly disorganized/catatonic behavior where information was inadequate or contradictory to support a more specific diagnosis.^[1] Similarly, Pervasive Developmental Disorder NOS covered autism spectrum-like symptoms not meeting criteria for autistic disorder, Asperger's disorder, or other specific subtypes, often used for individuals with social and communication impairments without restricted repetitive behaviors.^[2] Learning Disorder NOS addressed academic skill deficits that did not align with reading, mathematics, or written expression disorders, while Anxiety Disorder NOS and Mood Disorder NOS captured presentations like generalized anxiety or depressive symptoms falling short of major depressive disorder criteria.^[2] These categories were intentionally broad to avoid forcing ill-fitting diagnoses, though they sometimes led to diagnostic heterogeneity and reduced specificity in research and treatment planning.^[3] The transition to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5, published in 2013), marked a significant shift away from NOS toward more precise terminology to enhance clinical utility and reliability.^[2] NOS was largely eliminated, replaced by Other Specified Disorder—where the clinician explicitly notes the reason for not meeting full criteria (e.g., "Other Specified Schizophrenia Spectrum and Other Psychotic Disorder" for persistent auditory hallucinations)—and Unspecified Disorder, used when no rationale is provided, such as in emergencies.^[1] This change aimed to reduce vagueness; for instance, former categories like Dyssomnia NOS were refined by elevating conditions such as rapid eye movement sleep behavior disorder and restless legs syndrome to independent diagnoses based on accumulating research evidence.^[2] National trends from 1999 to 2010 indicated NOS diagnoses comprised a substantial portion of psychiatric classifications, particularly in outpatient settings, underscoring their prior prevalence before the DSM-5 revisions.^[4] Overall, the evolution from NOS reflects ongoing efforts in psychiatric nosology to balance inclusivity with diagnostic precision.^[2]

Definition and Purpose

Definition

"Not otherwise specified" (NOS) is a diagnostic subcategory used in medical classification systems such as the Diagnostic and Statistical Manual of Mental Disorders (DSM) and the International Classification of Diseases (ICD) to designate conditions that exhibit clinically significant symptoms resembling those of a particular disorder class but do not fully meet the criteria for any specific subtype within that class.^[5] This residual category accommodates presentations where the symptom pattern is present but incomplete, atypical in form, or insufficiently documented to assign a more precise diagnosis, ensuring that all observable clinical phenomena can be systematically recorded.^[6] NOS differs from related terms such as "atypical," which typically describes specific non-standard presentations with somewhat defined features (e.g., atypical features in major depressive disorder indicating certain symptom modifiers), and "residual," which refers to a subtype in disorders like schizophrenia characterized by persisting negative symptoms after an acute phase without prominent positive symptoms. Unlike these, NOS serves as a broad catch-all without implying a particular phase or modifier, focusing instead on the failure to fit established criteria.^[6] In both the DSM and ICD, NOS facilitates provisional diagnoses when full clinical information is unavailable, such as during initial evaluations or when symptoms are evolving, allowing clinicians to note the presence of a disorder while deferring specificity until further assessment.^[5]^[3] This application promotes comprehensive classification without forcing ill-fitting assignments, though it is intended as a temporary or infrequent option to minimize diagnostic ambiguity.

Role in Diagnostic Systems

The "not otherwise specified" (NOS) category serves as a residual classification in diagnostic systems such as the DSM and ICD, enabling clinicians to assign a diagnosis when patient symptoms do not fully align with established criteria for specific disorders or when insufficient information is available to determine a more precise category.^[7] This flexibility is particularly valuable in ambiguous cases, where rigid adherence to predefined criteria might otherwise exclude patients from receiving timely care, ensuring that atypical or subthreshold presentations—such as mixed anxiety and depressive symptoms or provisional psychotic episodes—are still documented and addressed.^[8] By providing this safety net, NOS prevents diagnostic gaps that could delay intervention, as evidenced by its frequent use in clinical settings where presentations do not conform to standard categories.^[4] In clinical practice, NOS facilitates the initiation of treatment without requiring exhaustive categorization, allowing providers to prescribe interventions like psychotropic medications for subthreshold conditions while gathering additional data for refinement.^[4] This approach supports patient management in diverse contexts, including primary care and emergency settings, where rapid decision-making is essential and full diagnostic clarity may not be immediately achievable.^[7] For instance, NOS codes enable provisional recording of conditions like unspecified anxiety disorders, promoting continuity of care and reducing the risk of misdiagnosis through premature specificity.^[8] NOS also plays a key role in epidemiological tracking by capturing uncategorized cases, which helps monitor the prevalence of atypical or emerging conditions that might otherwise evade standard surveillance systems.^[4] In systems like ICD-10, these categories aggregate data on residual presentations, contributing to public health research and resource allocation despite their inherent diagnostic uncertainty.^[8] Furthermore, NOS supports insurance coding and reimbursement by providing valid codes for billing when specific diagnoses are unavailable, ensuring administrative continuity and access to coverage for patients with incomplete classifications.^[9] This utility is critical during transitions between coding systems, such as from ICD-9 to ICD-10, where NOS equivalents maintain claim processing efficiency.^[9]

Historical Development

Origins in Classification Systems

The "not otherwise specified" (NOS) category emerged as a practical mechanism within early modern medical classification systems to address diagnostic uncertainty and incomplete information. In the International Classification of Diseases, Ninth Revision (ICD-9), endorsed by the World Health Organization in 1975, NOS served as a subcategory for conditions lacking sufficient detail to assign a more precise code, functioning as an equivalent to "unspecified" to ensure comprehensive coding without rigid categorization.^[10] This approach allowed clinicians and statisticians to record cases where symptoms or etiologies were documented but did not align perfectly with defined rubrics, reflecting the inherent variability in medical presentations. The adoption of NOS in psychiatric nosology closely followed with the publication of the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III), by the American Psychiatric Association in 1980. Here, NOS categories were incorporated across major diagnostic classes—such as affective disorders, anxiety disorders, and psychotic disorders—to capture heterogeneous symptom presentations that met general clinical thresholds but failed to satisfy the explicit criteria for specific subtypes.^[11] Developers emphasized that these residual designations provided essential flexibility, preventing the imposition of ill-fitting diagnoses on atypical or subthreshold cases while maintaining the manual's atheoretical, symptom-based framework grounded in empirical field trials.^[12] This shared rationale across ICD-9 and DSM-III stemmed from the developers' recognition of real-world diagnostic complexity, where rigid categories alone could exclude valid clinical entities; NOS thus acted as a catch-all to promote reliability, utility, and alignment with international standards like ICD-9, without assuming etiological knowledge.

Evolution in DSM

The revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM) in 1987, resulting in DSM-III-R, marked a significant expansion of the "not otherwise specified" (NOS) category, particularly within mood and anxiety disorder classifications. This edition introduced dedicated NOS subtypes, such as "mood disorder not otherwise specified" and "anxiety disorder not otherwise specified," to accommodate presentations that exhibited clinically significant symptoms but fell short of meeting full criteria for specific disorders like major depression or generalized anxiety disorder. These additions reflected efforts to address gaps in the DSM-III framework by providing more flexible diagnostic options for atypical or subthreshold cases, thereby improving the manual's applicability in clinical settings.^[13]^[14] The expansions in DSM-III-R were shaped by the American Psychiatric Association's (APA) Work Group to Revise DSM-III, which conducted comprehensive reviews of empirical data, including field trials and clinician feedback, to refine diagnostic criteria and reduce exclusionary hierarchies that had limited prior categorizations. Key publications from this process, such as the APA's preparatory reports on nosology, emphasized the need for NOS provisions to capture the heterogeneity of psychiatric presentations without forcing ill-fitting diagnoses. This iterative approach built on the foundational use of NOS in earlier DSM editions, enhancing its utility as a residual category while promoting greater diagnostic precision.^[12] By the publication of DSM-IV in 1994, the NOS category had been further standardized as a uniform specifier applicable across all major diagnostic axes, ensuring consistent application throughout the multiaxial system. The manual explicitly outlined criteria for invoking NOS: the disturbance must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning, yet not fulfill the full symptomatic requirements or duration for any specific disorder within the relevant category. This standardization aimed to minimize diagnostic ambiguity and support reliable clinical communication.^[4] The guidelines for NOS in DSM-IV were developed through the APA Task Force on DSM-IV, supported by specialized advisory work groups that integrated findings from a series of field trials and extensive literature syntheses. Seminal contributions from these groups, documented in APA technical bulletins and preparatory volumes like DSM-IV Sourcebook, underscored the category's role in bridging categorical limitations while avoiding overdiagnosis, thereby influencing its widespread adoption in psychiatric practice.^[12]

Application in Psychiatry

Use in DSM-IV

In the DSM-IV, the "Not Otherwise Specified" (NOS) category was employed when a patient's symptoms indicated a clinically significant disturbance within a specific family of disorders—such as anxiety, mood, or psychotic disorders—but did not fully meet the diagnostic criteria for any particular disorder in that category due to insufficient duration, severity, number of symptoms, or atypical presentation.^[15] This residual category allowed for the recognition of presentations that warranted clinical attention but lacked the specificity required for a more precise diagnosis, ensuring that subthreshold or mixed symptoms were not overlooked. NOS diagnoses were primarily placed on Axis I of the DSM-IV's multiaxial system, which encompassed all clinical disorders except personality disorders and mental retardation, including those with NOS designations for conditions like mood or anxiety disorders. For personality-related NOS, such as Personality Disorder NOS, placement occurred on Axis II, dedicated to enduring personality disorders and intellectual disabilities.^[16] This axial placement facilitated a comprehensive evaluation by distinguishing acute clinical issues from chronic personality traits. Documentation guidelines in DSM-IV emphasized the need for detailed descriptions of presenting symptoms to justify an NOS diagnosis and differentiate it from other categories, including the specification of how symptoms deviated from full criteria (e.g., atypical features or subthreshold intensity).^[17] Clinicians were instructed to note the predominant disturbances, their impact on functioning, and reasons why no other diagnosis applied, promoting transparency and aiding future reassessment or treatment planning.^[18]

Common Psychiatric NOS Diagnoses

In the DSM-IV framework, not otherwise specified (NOS) diagnoses served as residual categories for clinically significant psychiatric presentations that did not fully meet the criteria for more specific disorders within a given class. These categories were frequently applied in outpatient settings, where NOS diagnoses accounted for 49.5% of all psychiatric visits by 2007–2010, up from 41.8% in 1999–2002.^[4] Among these, mood, anxiety, and personality disorder NOS were particularly prevalent, reflecting the challenges in fitting diverse symptom profiles to rigid diagnostic thresholds. Mood disorder NOS (code 296.90) was designated for cases involving clinically significant depressive or manic symptoms that did not align with the full criteria for major depressive disorder, bipolar I or II disorder, cyclothymic disorder, or dysthymic disorder.^[19] This category often captured subthreshold or atypical mood disturbances, such as recurrent brief depressive episodes or mood symptoms with uncertain etiology. In clinical practice, depressive disorder NOS represented 50.9% of depressive disorder visits, while bipolar disorder NOS rose to 55.3% of bipolar-related visits during the study period, highlighting its substantial use in mood disorder contexts.^[4] Anxiety disorder NOS (code 300.00) applied to presentations with prominent anxiety symptoms that failed to meet the duration, severity, or specificity requirements for disorders like generalized anxiety disorder, panic disorder, or social phobia.^[15] Common examples included mixed anxiety states or anxiety symptoms intermixed with other features, such as somatic complaints without a clear panic or phobic focus. This diagnosis was especially common, comprising 61.9% of anxiety disorder visits by 2007–2010, up from 50.1% earlier.^[4] Personality disorder NOS (code 301.9) was used for enduring patterns of inner experience and behavior that deviated markedly from cultural expectations and caused distress or impairment, but did not meet the full criteria for any of the 10 specific personality disorders across clusters A, B, or C.^[20] It typically involved subthreshold traits from multiple disorders or mixed features falling just short of diagnostic thresholds, such as one criterion below for two or more personality disorders. In psychiatric outpatients, personality disorder NOS was the most frequent residual diagnosis, affecting 14.1% of patients and elevating the overall personality disorder prevalence to 45.5% when included. In broader samples, it accounted for 17% of all patients and 22% of those with any personality pathology.^[20]^[21]

Application in General Medicine

Use in ICD

In the International Classification of Diseases (ICD) systems, particularly ICD-9 and ICD-10, "not otherwise specified" (NOS) serves as a category for diagnoses where insufficient information is available to assign a more precise code, often represented as a fourth-digit subcategory of 9 in ICD-9-CM for unspecified conditions.^[10] For example, in ICD-9-CM, codes such as 001.9 denote cholera NOS, allowing coders to capture cases lacking detailed etiology or manifestation data.^[10] Similarly, in ICD-10, NOS codes appear at the end of diagnostic blocks, such as F99 for mental disorder, not otherwise specified, which encompasses unclassifiable mental health conditions due to known physiological factors or other unspecified causes. Unlike the Diagnostic and Statistical Manual of Mental Disorders (DSM), which prioritizes clinical diagnostic criteria for mental health professionals, the ICD places greater emphasis on standardized coding for administrative, statistical, and public health purposes, facilitating global morbidity and mortality tracking, resource allocation, and healthcare reimbursement.^[22] This administrative focus in ICD enables consistent data collection across diverse healthcare settings, contrasting with DSM's more specialized role in psychiatric treatment planning.^[22] The ICD's NOS provisions have been widely adopted globally by all 194 World Health Organization (WHO) Member States, with translations into 43 languages, supporting uniform health data reporting in both high- and low-income countries.^[23] In resource-limited settings, NOS codes help manage incomplete documentation by providing provisional classifications for epidemiological surveillance and service planning. As of 2025, over 120 countries utilize ICD for mortality statistics, underscoring its role in international health policy.^[24] In the latest revision, ICD-11 (effective 2022, with 2025 updates), NOS equivalents such as "unspecified" residual categories continue to allow for cases with inadequate details, maintaining compatibility with prior systems while enhancing precision through digital tools and linearizations for specific uses.^[25]^[26]

Examples in Non-Psychiatric Contexts

In the International Classification of Diseases (ICD), the category for neoplasms of unspecified behavior, coded under D49 in ICD-10, is applied to tumors where the benign or malignant nature cannot be determined based on available pathological or clinical information.^[27] This includes codes such as D49.9 for neoplasm of unspecified behavior of unspecified site, which is used when initial diagnostic evaluations, such as biopsies, yield inconclusive results regarding the tumor's behavior. Such classifications are provisional and often refined as further testing, like immunohistochemistry or imaging, provides clarity on the lesion's characteristics. Injury NOS, designated as T14.90 in ICD-10, refers to unspecified injuries where the nature of the trauma, body region, or external cause remains undetermined at the time of coding, particularly in high-pressure settings like emergency departments.^[28] This code is employed for initial encounters (T14.90XA) when detailed history or examination is limited, such as in cases of unconscious patients or rapid triage scenarios, and it serves as a placeholder until more specific codes from the S00-T88 range can be assigned based on subsequent assessments.^[29] In oncology, NOS designations for neoplasms are common in early-stage diagnoses, accounting for approximately 2-6% of all cancer cases, often representing cancers of unknown primary (CUP) under C80.1, where the origin remains elusive despite extensive workup.^[30] For instance, in non-small cell lung cancer (NSCLC), unspecified histology (NOS) constitutes up to 10% of initial diagnoses, typically due to limited biopsy material, but this rate has declined with advances in molecular pathology.^[31] In orthopedics, NOS codes like those for unspecified fractures (e.g., M84.30 for stress fracture, unspecified site) or injuries (e.g., S52.90 for unspecified forearm fracture) are frequently used in trauma coding, especially for emergency presentations where imaging or patient reports are incomplete, facilitating preliminary billing and epidemiological tracking while allowing later specificity.^[32]

Criticisms and Limitations

Diagnostic Ambiguity

The vagueness inherent in the "not otherwise specified" (NOS) category within diagnostic systems like the DSM-IV contributes significantly to inconsistent diagnostic practices in psychiatry. NOS serves as a catch-all for symptoms that do not fully align with established criteria for specific disorders, leading clinicians to frequently default to it when presentations are atypical or subthreshold. Studies indicate that clinicians applied NOS diagnoses in 30–50% of cases across various psychiatric conditions, reflecting the challenges in fitting complex or heterogeneous symptoms into rigid categorical frameworks.^[33] This high usage rate underscores the diagnostic ambiguity, as it allows for broad interpretation without standardized guidelines, resulting in varied application across practitioners. Inter-rater reliability for NOS assignments is particularly problematic, with studies demonstrating substantial variability in how clinicians classify cases under this category. For instance, in the diagnosis of pervasive developmental disorder not otherwise specified (PDD-NOS), inter-rater agreement yielded kappa values ranging from 0.18 to 0.65, indicating low to moderate reliability compared to higher agreement (kappa 0.67–0.95) for distinguishing pervasive developmental disorders from non-disorders.^[34] Similar issues arise in other NOS contexts, such as sleep disorders, where lower reliability estimates (Spearman correlations 0.08–0.53) have been reported due to the absence of explicit criteria, exacerbating discrepancies among diagnosticians.^[35] The potential for overuse of NOS as a "wastebasket" diagnosis further dilutes its specificity and undermines diagnostic precision. NOS categories have been criticized for encompassing a wide array of ill-defined conditions, allowing clinicians to assign them without rigorous validation, which blurs distinctions between disorders and reduces the overall utility of classification systems. This practice can lead to heterogeneous groupings that hinder consistent identification of underlying pathologies. Ethically, the ambiguity of NOS raises concerns about stigmatization, as patients receive a psychiatric label without a clear pathway to targeted treatment or prognosis. Vague diagnoses like NOS equivalents can perpetuate stigma by implying mental illness without providing actionable insights, potentially deterring patients from seeking care due to fears of social repercussions or ineffective interventions.^[36] This lack of specificity conflicts with principles of beneficence and non-maleficence, as it may expose individuals to unnecessary labeling while failing to address their needs adequately.

Effects on Treatment and Research

The use of "not otherwise specified" (NOS) diagnoses in psychiatric classification systems presents significant challenges to treatment planning, as these categories often lack tailored evidence-based guidelines, resulting in reliance on generic or off-label interventions. For instance, clinicians frequently prescribe psychotropic medications such as antipsychotics and mood stabilizers for NOS conditions without the support of clinical trials designed for full-criteria disorders, leading to increased off-label use that rose from 62.7% to 75.2% of NOS cases between 1999 and 2010.^[4] This approach can complicate insurance coverage and patient adherence, as treatments are not precisely matched to symptom profiles, potentially delaying optimal care. The diagnostic ambiguity inherent in NOS further hinders personalized treatment, as provisional or residual diagnoses like "other specified bipolar and related disorder" may prompt cautious, broad-spectrum pharmacotherapy rather than targeted therapies. In research, NOS categories impose limitations by complicating data aggregation and study design, as their heterogeneous nature—encompassing diverse symptom profiles and etiologies—defies consistent categorization across datasets. This heterogeneity reduces the reliability of meta-analyses and reproducibility of findings, as studies assuming uniform NOS groups often yield small effect sizes and fail to generalize, particularly in areas like personality or psychotic disorders where NOS serves as a catch-all. Consequently, funding for NOS-related investigations is often underprioritized, as traditional DSM frameworks fail to support precise etiological models, contributing to broader disinvestment in psychiatric drug development and precision approaches. Statistically, NOS diagnoses inflate "unknown" or subthreshold categories in health databases, skewing prevalence estimates and comorbidity rates that inform public policy. For example, among youth psychiatric visits in the US, NOS proportions for mood disorders climbed from 45.3% in 1999–2002 to 68.8% by 2007–2010, artificially elevating overall disorder statistics and prompting resource misallocation toward broad interventions rather than specific prevention strategies.^[37] This distortion affects policy decisions, such as funding allocations for mental health services, by obscuring true epidemiological patterns and hindering targeted reforms in classification systems.

Modern Alternatives

Changes in DSM-5

In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association (APA) in 2013, the longstanding "not otherwise specified" (NOS) category was eliminated across all diagnostic classes and replaced with two distinct alternatives: "other specified disorder" and "unspecified disorder."^[2] The "other specified disorder" option enables clinicians to explicitly describe the reason why the full diagnostic criteria for a particular disorder are not met, such as subthreshold symptom severity or atypical presentations, thereby allowing for tailored notation (e.g., "other specified depressive disorder, short-duration depressive episode").^[38] In contrast, the "unspecified disorder" category is reserved for situations where the clinician provides a diagnosis without detailing the specific rationale, often due to insufficient information, patient privacy concerns, or emergency settings where full assessment is not feasible.^[38] This revision aimed to enhance diagnostic precision and clinical utility by addressing the vagueness inherent in NOS, which previously encompassed a heterogeneous array of conditions that did not fit established criteria, leading to inconsistent application and reduced reliability in clinical and research contexts.^[2] According to APA documentation, the change promotes more informative communication between providers and reduces confusion for patients and stakeholders, aligning the manual more closely with international standards like the ICD while minimizing the overuse of residual categories that obscured meaningful distinctions.^[38] For transitioning existing DSM-IV NOS diagnoses to DSM-5, the APA provided no rigid conversion rules but recommended comprehensive re-evaluation of cases using the updated criteria, as many NOS presentations could now align with newly defined or restructured disorders (e.g., autism spectrum disorder absorbing previous pervasive developmental disorder NOS).^[2] Clinicians were encouraged to apply the "other specified" or "unspecified" designations judiciously during this shift to maintain continuity in patient care while adopting the more granular framework.^[39]

Updates in ICD-11

The International Classification of Diseases, 11th Revision (ICD-11), effective from January 1, 2022, significantly refines the approach to residual and unspecified diagnostic categories previously known as "not otherwise specified" (NOS) in ICD-10, emphasizing greater specificity through new granular codes and postcoordination mechanisms to minimize broad, ambiguous groupings.^[25]^[40] In mental and behavioral disorders, ICD-11 eliminates or reduces reliance on NOS equivalents by introducing dimensional assessments and specific diagnostic entities, such as complex post-traumatic stress disorder (6B41), prolonged grief disorder (6B42), and binge eating disorder (6B82), which replace vague residual categories like "other specified feeding or eating disorder."^[41] This shift integrates functioning evaluations, using tools like the WHO Disability Assessment Schedule (WHODAS 2.0) to qualify severity and impairment, thereby providing a more nuanced framework that links symptoms to real-world impact without defaulting to unspecified codes.^[41] For personality disorders, a single overarching category with severity ratings and trait qualifiers supplants multiple NOS-type subtypes, further curtailing ambiguous diagnoses.^[41] In contrast, ICD-11 retains limited NOS-like residuals in select non-psychiatric domains for practical coding where specificity is constrained by available data, particularly in neoplasms. The former "neoplasms, NOS" category from related systems like ICD-O is eliminated, with uncertain behavior neoplasms recoded into dedicated blocks (e.g., 2F70–2F7Z) and unknown behavior into others (e.g., 2F90–2F9Z), enhanced by extension codes for histology and topography to ensure precision.^[42] Unspecified residuals (marked with ".Z") persist only as a last resort for clinically diagnosed but unconfirmed cases, such as "malignant neoplasms of colon, unspecified" (2B90.Z), supporting statistical completeness without encouraging overuse.^[40]^[42] The World Health Organization (WHO) endorsed ICD-11 in May 2019, with global implementation beginning in 2022; as of 2025, over 45 countries have adopted it for mortality, morbidity, and health management, bolstered by a February 2025 update incorporating expanded modules for traditional medicine and interoperability.^[26]^[43] WHO provides comprehensive training resources, including an online ICD-11 Training Package with modules on coding specificity and transition guides, available via the ICD-API and CodeFusion tools to facilitate adoption and reduce NOS misuse in practice.^[44]^[45]

References

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ICD-11 Implementation - World Health Organization (WHO)
Feb 12, 2025 · The new Revision of ICD was endorsed by the World Health Assembly at the 72 nd meeting in 2019, and came into effect globally on 1 January 2022.Missing: limited | Show results with:limited
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https://www.who.int/standards/classifications/frequently-asked-questions/icd-11-implementation