Chapter 18 — Symptoms, Signs and Abnormal Clinical and Laboratory Findings
Symptom codes: when they are acceptable, when they may sit alongside a definitive diagnosis, and the specific rules for coma scale, NIHSS, SIRS, repeated falls and R99.
Chapter 18 is where a code goes when no diagnosis classifiable elsewhere has been recorded. Symptom codes are acceptable when no related definitive diagnosis has been established, may be added alongside a definitive diagnosis when the symptom is not routinely associated with it, and must never be used when a combination code already carries the symptom.
When are symptom codes used?#
| Situation | Rule |
|---|---|
| No related definitive diagnosis established (confirmed) by the provider | ALWAYS Symptom and sign codes are acceptable for reporting purposes |
| A definitive diagnosis is established, and the symptom is not routinely associated with it — for example the various signs and symptoms of complex syndromes | ALWAYS The symptom may be reported in addition. The definitive diagnosis code is sequenced before the symptom code |
| A definitive diagnosis is established and the symptom is routinely associated with it | NEVER Not assigned as an additional code, unless the classification instructs otherwise |
| A combination code identifies both the definitive diagnosis and common symptoms of it | NEVER An additional code is not assigned for the symptom |
The specific Chapter 18 guidelines#
| Topic | Rule |
|---|---|
Repeated falls — R29.6 | For encounters where a patient has recently fallen and the reason for the fall is being investigated |
History of falling — Z91.81 | For a patient who has fallen in the past and is at risk for future falls. ALWAYS Both R29.6 and Z91.81 may be assigned together when appropriate |
Coma — R40.20 | Assigned when the underlying cause of the coma is not known, or the cause is a traumatic brain injury and the coma scale is not documented |
| Medically induced coma or a sedated patient | NEVER Do not report codes for unspecified coma, nor individual or total Glasgow coma scale scores |
Coma scale codes R40.21- to R40.24- | May be used with traumatic brain injury codes. NEVER Cannot be used with R40.2A nontraumatic coma due to underlying condition. Primarily for trauma registries but usable in any setting where the information is collected. Sequenced after the diagnosis code(s) |
| Completing the scale | One code from each subcategory is needed to complete the scale. The 7th character indicates when the scale was recorded, and must match for all three codes |
| Minimum reporting | At a minimum, report the initial score documented on presentation at your facility — which may be an EMT score or an emergency department score. A facility may choose to capture multiple scores |
R40.24- total score only | Assigned when only the total score is documented and not the individual scores |
| Multiple scores within 24 hours of admission | Assign only the code for the score at the time of admission. ICD-10-CM does not classify coma scores reported after admission but less than 24 hours later |
| Functional quadriplegia | EXCEPTION Guideline deleted effective October 1, 2017 |
| SIRS due to a non-infectious process | 1the code for the underlying condition, such as the injury2R65.10 SIRS of non-infectious origin without acute organ dysfunction, or R65.11 with acute organ dysfunction3the appropriate code(s) for the specific type of organ dysfunction, in addition to R65.11 |
| SIRS where it cannot be determined whether the acute organ dysfunction is associated with the SIRS or due to another condition | QUERY Query the provider |
Death NOS — R99 | For the very limited circumstance where a patient who has already died is brought into an emergency department or other health care facility and is pronounced dead on arrival. NEVER It does not represent the discharge disposition of death |
NIH stroke scale — R29.7-- | May be used with acute stroke codes I60–I63 to identify neurological status and stroke severity. Sequenced after the acute stroke diagnosis code(s). At a minimum report the initial score documented |
Practice questions#
Q1A patient is admitted with pneumonia. The record documents cough and fever, both typical of pneumonia. What is assigned?
- AThe pneumonia code, plus codes for cough and fever
- BThe pneumonia code only
- CThe cough and fever codes only
- DThe pneumonia code plus fever only
Show answer & rationale
Correct answer: B. The pneumonia code only
Rationale. Section I.C.18.b states that signs or symptoms associated routinely with a disease process should not be assigned as additional codes, unless otherwise instructed by the classification. Section I.B.5 states the same rule generally. Symptoms not routinely associated with the diagnosis may be reported in addition, sequenced after the definitive diagnosis.
Q2A patient with a traumatic brain injury has Glasgow coma scale components documented in the emergency department. How are the coma scale codes sequenced and structured?
- ABefore the injury codes, with any 7th characters
- BAfter the diagnosis codes, one from each subcategory, with matching 7th characters
- CAfter the diagnosis codes, using only the total score code
- DThey may not be used with traumatic brain injury codes
Show answer & rationale
Correct answer: B. After the diagnosis codes, one from each subcategory, with matching 7th characters
Rationale. Section I.C.18.e.1 states that the coma scale codes can be used in conjunction with traumatic brain injury codes, that they should be sequenced after the diagnosis codes, that these codes — one from each subcategory — are needed to complete the scale, and that the 7th character indicating when the scale was recorded should match for all three codes. R40.24- is used when only the total score is documented.
Q3A trauma patient develops SIRS with acute renal dysfunction, and no infection is documented. What is assigned?
- A
R65.20and the renal dysfunction code - BThe injury code,
R65.11, and the code for the acute renal dysfunction - CThe injury code and
R65.10 - D
R65.11as principal diagnosis
Show answer & rationale
Correct answer: B. The injury code, R65.11, and the code for the acute renal dysfunction
Rationale. Section I.C.18.g states that when SIRS is documented with a noninfectious condition and no subsequent infection is documented, the code for the underlying condition such as an injury should be assigned, followed by R65.10 SIRS without acute organ dysfunction or R65.11 SIRS with acute organ dysfunction, and that if an associated acute organ dysfunction is documented the appropriate codes for the specific type of organ dysfunction should be assigned in addition to R65.11.
Q4A patient is brought to the emergency department already deceased and is pronounced dead on arrival. What may be assigned?
- A
R99 - BThe discharge disposition code only
- C
R40.20 - DNo code is available for this circumstance
Show answer & rationale
Correct answer: A. R99
Rationale. Section I.C.18.h states that code R99, ill-defined and unknown cause of mortality, is only for use in the very limited circumstance when a patient who has already died is brought into an emergency department or other healthcare facility and is pronounced dead upon arrival, and that it does not represent the discharge disposition of death.
Q5A patient has fallen twice in the last month and the cause is being investigated at this encounter. The patient is also documented as being at risk for future falls. What may be assigned?
- A
R29.6only - B
Z91.81only - CBoth
R29.6andZ91.81 - DNeither, without an external cause code
Show answer & rationale
Correct answer: C. Both R29.6 and Z91.81
Rationale. Section I.C.18.d states that R29.6 repeated falls is for use for encounters when a patient has recently fallen and the reason for the fall is being investigated, that Z91.81 history of falling is for use when a patient has fallen in the past and is at risk for future falls, and that when appropriate both codes may be assigned together.
Scenarios#
A patient is seen in the office for episodic dizziness. A full workup is performed and no definitive diagnosis is established by the end of the encounter.
Show coded answer & rationale
| Seq | Code | Description |
|---|---|---|
| 1 | R42 | Dizziness and giddiness — first-listed |
Rationale. Section I.C.18.a states that codes describing symptoms and signs are acceptable for reporting purposes when a related definitive diagnosis has not been established (confirmed) by the provider. Section IV.H is the reason a working or suspected diagnosis cannot be substituted in an outpatient setting: probable, suspected, questionable, rule out, compatible with, consistent with and working diagnosis are not coded — the condition is coded to the highest degree of certainty for that encounter. Section I.B.18 confirms that symptom codes have acceptable, even necessary, uses.
Guideline: Section I.C.18.a; Section IV.H; Section I.B.18
A patient is admitted with an acute ischaemic stroke. The stroke coordinator documents an NIH stroke scale score of 12 on presentation.
Show coded answer & rationale
| Seq | Code | Description |
|---|---|---|
| 1 | I63.- | Cerebral infarction, the applicable code — principal diagnosis |
| 2 | R29.712 | NIHSS score 12 — verify in the Tabular List; sequenced after the acute stroke code |
Rationale. Section I.C.18.i states that the NIHSS codes R29.7-- can be used in conjunction with acute stroke codes I60-I63 to identify the patient's neurological status and the severity of the stroke, that the stroke scale codes should be sequenced after the acute stroke diagnosis codes, and that at a minimum the initial score documented should be reported. Section I.B.14 lists NIHSS among the items that may be coded from a clinician other than the patient's provider, and restricts it to a secondary diagnosis.
Guideline: Section I.C.18.i, I.B.14
A ventilated patient in the intensive care unit is under continuous sedation. Nursing documentation records a low Glasgow coma scale total while sedated.
Show coded answer & rationale
| Seq | Code | Description |
|---|---|---|
| 1 | — | no unspecified coma code and no Glasgow coma scale codes are assigned |
Rationale. Section I.C.18.e states plainly that codes for unspecified coma and individual or total Glasgow coma scale scores are not reported for a patient with a medically induced coma or a sedated patient. The score in the chart reflects sedation, not the patient's neurological status, and reporting it would misrepresent severity.
Guideline: Section I.C.18.e
Primary sources#
- ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027CMS — the source document for every page on this site (effective 1 Oct 2026)
- NCHS ICD-10-CM files — Tabular List, Index, POA exempt listOfficial code files, addenda and the list of codes exempt from POA reporting
- ICD-10 Coordination and Maintenance CommitteeWhere code proposals are debated; agendas, summaries and meeting materials
- CMS ICD-10 homeCode sets, transition guidance and Medicare coding policy
- AHA Coding ClinicOfficial coding advice from the AHA Central Office — subscription required
- HHS OIG Work PlanActive audit topics — useful for prioritising internal coding audits
- MEDESUN Medical Coding AcademyTraining, credential preparation and audit services by the author