ICD-10-PCS Code For Olfactory: Procedure Code Group Overview

The International Classification of Diseases, Tenth Revision, Procedure Coding System (ICD-10-PCS) code group 4A08 includes procedures performed to measure physiological function in the olfactory system. These ICD-10-PCS codes are used for inpatient documentation when clinicians perform objective tests to determine the level of a patients sense of smell at a specific point in time. Accurate coding within the ICD-10-PCS 4A08 group is essential for proper inpatient reimbursement, as it captures the procedure performed and supports clinical documentation accuracy.

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Olfactory Measurement Procedure Overview

Procedures in this group involve measuring the sense of smell to determine olfactory acuity and function in the physiological systems body system. These measurement procedures assess the olfactory (smell) sensory function at a point in time using external approaches and objective testing methods. Accurate ICD-10-PCS coding of these measurements ensures inpatient records reflect the evaluation performed and supports correct case mix assignment and reimbursement.

Code Attributes

Character	ICD-10-PCS Category	Code Group Details
4	Section	Measurement and Monitoring
A	Body System	Physiological Systems
0	Operation	Measurement
8	Body Part	Olfactory

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ICD-10-PCS Code For Olfactory: Procedure Code Group Overview

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Olfactory Measurement Procedure Overview

Code Attributes

Character	ICD-10-PCS Category	Code Group Details
4	Section	Measurement and Monitoring
A	Body System	Physiological Systems
0	Operation	Measurement
8	Body Part	Olfactory

When to Use

Use a code from this group when a clinician performs an objective assessment or standardized test of olfactory function during an inpatient encounter. These codes apply when the procedure documents a measured level of smell acuity rather than therapeutic or surgical intervention.

ICD-10-PCS Codes

1 rows

ICD-10-PCS Code	Description
4A08X0Z	Measurement of Olfactory Acuity, External Approach

Typical Clinical Scenarios

An elderly inpatient admitted after a stroke affecting the frontal lobes reports new onset anosmia and inability to detect odors, raising concern for acute olfactory dysfunction impacting safety (eg, inability to detect smoke or spoiled food). Neurology orders an objective bedside olfactory acuity assessment using standardized external odorant kits to document the level of smell function during the acute hospital stay. Typical codes: 4A08X0Z
A middle-aged patient hospitalized electively for comprehensive evaluation of chronic sinonasal disease and persistent decreased smell after sinonasal surgery undergoes standardized external smell testing to quantify olfactory impairment as part of the inpatient diagnostic workup and to guide further ENT management. The measurement documents baseline olfactory acuity while the patient is in the facility for planned assessment. Typical codes: 4A08X0Z
A trauma patient in the inpatient unit with facial fractures and suspected olfactory nerve injury has serial external olfactory acuity measurements performed to track recovery and to determine the current level of smell function as part of complication monitoring after the injury. The tests are performed at defined points in time during the hospital course to document physiologic function. Typical codes: 4A08X0Z

Related Codes

4A00-CENTRAL-NERVOUS-MEASUREMENT

ICD-10-PCS Code For Central Nervous: Procedure Code Group Overview

4A01-PERIPHERAL-NERVOUS-MEASUREMENT

ICD-10-PCS Code For Peripheral Nervous: Procedure Code Group Overview

4A02-CARDIAC-MEASUREMENT

ICD-10-PCS Code For Cardiac: Procedure Code Group Overview

4A03-ARTERIAL-MEASUREMENT

ICD-10-PCS Code For Arterial: Procedure Code Group Overview

4A04-VENOUS-MEASUREMENT

ICD-10-PCS Code For Venous: Procedure Code Group Overview

4A05-CIRCULATORY-MEASUREMENT

ICD-10-PCS Code For Circulatory: Procedure Code Group Overview

4A06-LYMPHATIC-MEASUREMENT

ICD-10-PCS Code For Lymphatic: Procedure Code Group Overview

4A07-VISUAL-MEASUREMENT

ICD-10-PCS Code For Visual: Procedure Code Group Overview

4A09-RESPIRATORY-MEASUREMENT

ICD-10-PCS Code For Respiratory: Procedure Code Group Overview

4A0B-GASTROINTESTINAL-MEASUREMENT

ICD-10-PCS Code For Gastrointestinal: Procedure Code Group Overview

Showing 1–10 of 16

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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When to Use

ICD-10-PCS Codes

1 rows

ICD-10-PCS Code	Description
4A08X0Z	Measurement of Olfactory Acuity, External Approach

Typical Clinical Scenarios

An elderly inpatient admitted after a stroke affecting the frontal lobes reports new onset anosmia and inability to detect odors, raising concern for acute olfactory dysfunction impacting safety (eg, inability to detect smoke or spoiled food). Neurology orders an objective bedside olfactory acuity assessment using standardized external odorant kits to document the level of smell function during the acute hospital stay. Typical codes: 4A08X0Z
A middle-aged patient hospitalized electively for comprehensive evaluation of chronic sinonasal disease and persistent decreased smell after sinonasal surgery undergoes standardized external smell testing to quantify olfactory impairment as part of the inpatient diagnostic workup and to guide further ENT management. The measurement documents baseline olfactory acuity while the patient is in the facility for planned assessment. Typical codes: 4A08X0Z
A trauma patient in the inpatient unit with facial fractures and suspected olfactory nerve injury has serial external olfactory acuity measurements performed to track recovery and to determine the current level of smell function as part of complication monitoring after the injury. The tests are performed at defined points in time during the hospital course to document physiologic function. Typical codes: 4A08X0Z

Related Codes

4A00-CENTRAL-NERVOUS-MEASUREMENT

ICD-10-PCS Code For Central Nervous: Procedure Code Group Overview

4A01-PERIPHERAL-NERVOUS-MEASUREMENT

ICD-10-PCS Code For Peripheral Nervous: Procedure Code Group Overview

4A02-CARDIAC-MEASUREMENT

ICD-10-PCS Code For Cardiac: Procedure Code Group Overview

4A03-ARTERIAL-MEASUREMENT

ICD-10-PCS Code For Arterial: Procedure Code Group Overview

4A04-VENOUS-MEASUREMENT

ICD-10-PCS Code For Venous: Procedure Code Group Overview

4A05-CIRCULATORY-MEASUREMENT

ICD-10-PCS Code For Circulatory: Procedure Code Group Overview

4A06-LYMPHATIC-MEASUREMENT

ICD-10-PCS Code For Lymphatic: Procedure Code Group Overview

4A07-VISUAL-MEASUREMENT

ICD-10-PCS Code For Visual: Procedure Code Group Overview

4A09-RESPIRATORY-MEASUREMENT

ICD-10-PCS Code For Respiratory: Procedure Code Group Overview

4A0B-GASTROINTESTINAL-MEASUREMENT

ICD-10-PCS Code For Gastrointestinal: Procedure Code Group Overview

Showing 1–10 of 16

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

ICD-10-PCS Code For Olfactory: Procedure Code Group Overview

Sign up for ICD-10-PCS Code For Olfactory: Procedure Code Group Overview policy alerts

Olfactory Measurement Procedure Overview

Code Attributes

ICD-10-PCS Code For Olfactory: Procedure Code Group Overview

Sign up for ICD-10-PCS Code For Olfactory: Procedure Code Group Overview policy alerts

Olfactory Measurement Procedure Overview

Code Attributes

When to Use

ICD-10-PCS Codes

Typical Clinical Scenarios

Related Codes

What procedure does ICD-10-PCS code group 4A08 represent?

Which specific ICD-10-PCS code is listed in this procedure group?

In which ICD-10-PCS section and body system is the 4A08 group categorized?

Why is accurate coding in the 4A08 group important for inpatient care?

What approach and operation type are used for procedures in this group?

References

When to Use

ICD-10-PCS Codes

Typical Clinical Scenarios

Related Codes

What procedure does ICD-10-PCS code group 4A08 represent?

Which specific ICD-10-PCS code is listed in this procedure group?

In which ICD-10-PCS section and body system is the 4A08 group categorized?

Why is accurate coding in the 4A08 group important for inpatient care?

What approach and operation type are used for procedures in this group?

References