While supplies last! Free 2022 Essentials of Interventional Radiology Coding book with every ICD10monitor webcast order. No code required. Order now >

Conditions classified in Chapter 18 of ICD-10-CM include symptoms, signs, and abnormal clinical and laboratory findings that do not have a classifiable diagnosis listed elsewhere in the medical record. However, not all sign and symptom codes are classified in Chapter 18.

Some signs and symptoms are classified in the body system chapters. Before assigning a code from Chapter 18, the medical record must be reviewed to determine if the symptom or sign relates to a more specific diagnosis that is documented in the medical record, and the alphabetic index must be referenced to determine whether the symptom or sign is classified in a body system chapter instead of Chapter 18.

Symptoms and Signs Routinely Associated with a Definitive Diagnosis

Symptoms and signs often are documented along with the definitive diagnosis. Determining which signs and symptoms routinely are associated with a definitive diagnosis and which are not is relatively easy in some cases, but more difficult in others. For example, when a patient presents with fever, sore throat, headache, body aches, and chilling due to influenza Type A virus, it is relatively easy to determine that the only code that should be reported is the code for influenza (J11.1), because all of the symptoms documented are routinely associated with the flu. In the case of a 90-year-old patient with essential tremor (G25.0) and unsteadiness on feet (R26.81), both conditions would be reported even though essential tremor sometimes is associated with gait changes, such as unsteadiness when walking. However, because the unsteadiness on feet is not commonly or routinely associated with essential tremor, it actually may be a symptom or sign of another medical condition, and so it should be reported additionally.

Symptoms and Signs Classified in the Body System Chapters

There is an Excludes2 note that is helpful in identifying four classifications of conditions that are not included in Chapter 18. These conditions include:

  • Abnormal findings on antenatal screening of mother (O28.-)
  • Certain conditions originating in the perinatal period (P04-P96)
  • Signs and symptoms classified in the body system chapters
  • Signs and symptoms of the breast (N63, N64.5)

Abnormal Findings on Antenatal Screening of Mother

Category O28, Abnormal findings on antenatal screening of mother, contains codes for the general type of abnormal finding. Laboratory abnormal findings include hematological (O28.0), biochemical (O28.1), and cytological (O28.2) findings. Radiological abnormal findings include ultrasonic (O28.3) and other radiological studies (O28.4). There is also a code for abnormal chromosomal and genetic findings (O28.5), as well as codes for other abnormal findings (O28.8) and unspecified abnormal findings (O28.9). During pregnancy, abnormal findings would be reported with codes in Category O28 instead of codes from Chapter 18.

Certain Conditions Originating in the Perinatal Period

Symptoms, signs, and abnormal findings for conditions originating in the perinatal period are found throughout Chapter 16 of ICD-10-CM. Conditions such as neonatal jaundice NOS (P59.9), transient neonatal neutropenia (P61.5), and vomiting of newborn (P92.0-) are examples of some of the symptoms, signs, and abnormal findings classified in Chapter 16 that should be reported instead of codes from Chapter 18.

Signs and Symptoms Classified in Body System Chapters

Many signs and symptoms that relate to specific body systems are classified in the body system chapters. This was the case in ICD-9-CM and remains the case in ICD-10-CM, but in the latter, some additional signs and symptoms now are classified in the body system chapters.

Sleep disturbances classified in subcategory 780.5 in the Signs and Symptoms chapter of ICD-9-CM are now found in the Respiratory System chapter in ICD-10-CM. The table below, taken from the 2014 ICD-9-to-ICD-10 GEMs, lists the ICD-9-CM sign or symptoms code and the corresponding ICD-10-CM code in the Respiratory System chapter.

ICD-9-CM Code

ICD-10-CM Code

780.50 Sleep disturbance, unspecified

G47.9 Sleep disorder, unspecified

780.51 Insomnia with sleep apnea, unspecified

780.53 Hypersomnia with sleep apnea, unspecified

780.57 Unspecified sleep apnea

G47.30 Sleep apnea, unspecified

780.52 Insomnia unspecified

G47.00 Insomnia, unspecified

780.54 Hypersomnia, unspecified

G47.10 Hypersomnia, unspecified

780.55 Disruption of 24-hour sleep wake cycle, unspecified

G47.20 Circadian rhythm sleep disorder, unspecified type

780.56 Dysfunctions associated with sleep stages or arousal from sleep

780.59 Other sleep disturbances

G47.8 Other sleep disorders


Gangrene, not otherwise specified, is another example of a condition previously classified in the symptoms and signs chapter in ICD-9-CM that has been reclassified to a body system chapter, specifically the circulatory system chapter, in ICD-10-CM. Gangrene is a complication of cell death (necrosis) characterized by tissue decay that most often is caused by ischemia (insufficient blood supply) or infection. In ICD-9-CM, gangrene was reported with code 785.4, but it now is classified with other and unspecified disorders of the circulatory system and is reported with code I96. It should be noted that gangrene associated with atherosclerosis and other peripheral vascular diseases, diabetes, hernia, and certain other conditions is excluded from code I96.

Signs and Symptoms of the Breast

One common symptom of the breast not included in Chapter 18 of ICD-10-CM is a breast lump, which is listed with other disorders of the breast in the genitourinary system chapter. If the breast lump has not been more specifically diagnosed as a solitary cyst (N60.0-), fibroadenoma (D24.-), malignant neoplasm (C50.-), or other specific condition, it is reported with code N63, Unspecified lump of breast. Other signs and symptoms of the breast found in the genitourinary system chapter include induration of breast (N64.51), nipple discharge (N64.52), retraction of nipple (N64.53), and other signs and symptoms of the breast (N64.59).


This article covers only two factors to be considered when reporting codes from Chapter 18 – whether or not the signs and symptoms routinely are associated with a documented definitive diagnosis, and whether the sign or symptom should be reported with a code from one of the body system chapters. However, prior to assigning codes for symptoms, signs, and abnormal findings, all guidelines should be reviewed. Guidelines related to symptoms, signs and abnormal findings are found in a number of sections, including the General Coding Guidelines (Section I.B.4,5,and 6), the Chapter-Specific Guidelines (Section I.C.18), Selection of Principal Diagnosis (Section II.A), Reporting Additional Diagnosis (Section III.B), and Diagnostic Coding and Reporting Guidelines for Outpatient Services (Section IV.D and P). Taking time to review the guidelines, along with the notes at the beginning of Chapter 18 and coding instructions listed at the category, subcategory, and code levels, should ensure that the correct sign, symptom, or abnormal finding code is assigned.

About the Author

Lauri Gray, RHIT, CPC, has worked in the health information management field for 30 years. She began her career as a health records supervisor in a multi-specialty clinic. Most recently she has worked as a clinical technical editor of coding and reimbursement print and electronic products. She has also taught medical coding at the College of Eastern Utah. Areas of expertise include: ICD-10-CM, ICD-10-PCS, ICD-9-CM diagnosis and procedure coding, physician coding and reimbursement, claims adjudication processes, third-party reimbursement, RBRVS and fee schedule development. She is a member of the American Academy of Professional Coders (AAPC) and the American Health Information Management Association (AHIMA).

Contact the Author


To comment on this article please go to editor@icd10monitor.com


You May Also Like

Leave a Reply

Your Name(Required)
Your Email(Required)