Chapter 18: Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00–R99)

Symptoms and abnormal clinical or laboratory findings that do not yet point to a specific diagnosis: pain, fever, cough, dizziness, abnormal blood results and abnormal imaging findings. These are among the most used codes in everyday practice.

Chapter 18 spans codes R00–R99 in the FY2027 ICD-10-CM tabular list. This guide explains 98 of its most common codes — select a code for its official description, a plain-English explanation and a note on when the code is used.

ICD-10 Chapter 18: Symptoms, Signs & Abnormal Findings — illustrative image

Codes in this chapter

Code	Official description	In plain words
R00.0	Tachycardia, unspecified	Tachycardia is a fast heart rate; here the rhythm type is not specified.
R00.1	Bradycardia, unspecified	Bradycardia is a slow heart rate; here the rhythm type is not specified.
R00.2	Palpitations	Palpitations are an awareness of the heartbeat — racing, pounding or fluttering — recorded as a symptom.
R01.1	Cardiac murmur, unspecified	A cardiac murmur is an extra heart sound heard with a stethoscope; here its type and significance are not specified.
R03.0	Elevated blood-pressure reading, without diagnosis of hypertension	An elevated blood-pressure reading recorded at a visit, in a person who has not been diagnosed with hypertension.
R04.0	Epistaxis	Epistaxis is bleeding from the nose (a nosebleed).
R04.2	Hemoptysis	Haemoptysis is coughing up blood or blood-stained sputum from the airways or lungs.
R05.1	Acute cough	An acute cough is a cough present for a short time (under three weeks), usually with a respiratory infection.
R05.3	Chronic cough	A chronic cough is a cough lasting more than eight weeks in adults, needing a search for causes such as reflux, asthma or medicines.
R05.9	Cough, unspecified	Cough recorded as a symptom without its duration or cause being specified.
R06.00	Dyspnea, unspecified	Dyspnoea is difficult or uncomfortable breathing; the pattern is not specified here.
R06.01	Orthopnea	Orthopnoea is breathlessness when lying flat that is relieved by sitting up, often a sign of heart failure.
R06.02	Shortness of breath	Shortness of breath is the sensation of not getting enough air, recorded as a symptom while the cause is assessed.
R06.09	Other forms of dyspnea	Other forms of dyspnoea (difficult breathing) not covered by the specific dyspnoea codes.
R06.2	Wheezing	Wheezing is a high-pitched whistling sound when breathing, usually on breathing out, from narrowed airways.
R07.0	Pain in throat	Pain in the throat, recorded as a symptom without a cause being coded.
R07.1	Chest pain on breathing	Chest pain that is felt on breathing (pleuritic-type pain).
R07.2	Precordial pain	Precordial pain is pain felt over the front of the chest near the heart.
R07.89	Other chest pain	Other chest pain: chest pain patterns not covered by the specific chest-pain codes, such as chest wall pain.
R07.9	Chest pain, unspecified	Chest pain recorded as a symptom while its cause (heart, lung, muscle or other) is being assessed.
R09.02	Hypoxemia	Hypoxaemia is a low level of oxygen in the blood, usually measured by a pulse oximeter or blood gas.
R09.81	Nasal congestion	Nasal congestion is a blocked, stuffy nose from swollen nasal tissues.
R09.82	Postnasal drip	Postnasal drip is mucus running down the back of the throat from the nose and sinuses, causing throat clearing and cough.
R10.13	Epigastric pain	Epigastric pain is pain in the upper central abdomen, below the ribs, often from the stomach or duodenum.
R10.31	Right lower quadrant pain	Pain in the right lower quadrant of the abdomen, the area over the appendix, recorded as a symptom.
R10.32	Left lower quadrant pain	Pain in the left lower quadrant of the abdomen, often from the sigmoid colon, recorded as a symptom.
R10.84	Generalized abdominal pain	Generalised abdominal pain is pain spread across the abdomen rather than in one spot.
R10.9	Unspecified abdominal pain	Abdominal pain recorded as a symptom while the cause is being assessed.
R11.0	Nausea	Nausea is the feeling of needing to vomit, recorded on its own without vomiting.
R11.2	Nausea with vomiting, unspecified	Nausea occurring together with vomiting, recorded as symptoms while the cause is assessed.
R12	Heartburn	Heartburn is a burning feeling rising in the chest from acid reflux into the gullet.
R13.10	Dysphagia, unspecified	Dysphagia is difficulty swallowing food, drink or saliva; the phase affected is not specified here.
R14.0	Abdominal distension (gaseous)	Abdominal distension is bloating or swelling of the abdomen, here specified as gaseous (from gas).
R17	Unspecified jaundice	Jaundice is yellowing of the skin and eyes from raised bilirubin in the blood; cause not specified here.
R19.4	Change in bowel habit	A change in bowel habit means a persistent change in how often stools are passed or their consistency.
R19.7	Diarrhea, unspecified	Diarrhoea means frequent loose or watery stools; the cause is not specified here.
R20.0	Anesthesia of skin	Anaesthesia of skin here means loss of feeling (numbness) in an area of skin.
R20.2	Paresthesia of skin	Paraesthesia is abnormal skin sensation such as pins and needles, tingling or burning without an obvious stimulus.
R21	Rash and other nonspecific skin eruption	A rash is a change in the skin's appearance or texture; this code is for a nonspecific skin eruption while the cause is assessed.
R22.0	Localized swelling, mass and lump, head	A localised swelling, lump or mass in the head, recorded as a finding.
R23.2	Flushing	Flushing is a sudden reddening and warmth of the skin, especially of the face and neck.
R25.1	Tremor, unspecified	Tremor is involuntary rhythmic shaking of a body part; the type and cause are not specified here.
R25.2	Cramp and spasm	Cramp and spasm mean sudden involuntary muscle contractions, such as leg cramps.
R26.2	Difficulty in walking, not elsewhere classified	Difficulty in walking not classified to a specific gait disorder, recorded while the cause is assessed.
R26.89	Other abnormalities of gait and mobility	Other abnormalities of gait and walking pattern not covered by specific gait codes.
R29.6	Repeated falls	Repeated falls means a person has fallen more than once, recorded while causes (such as balance, medicines or weakness) are assessed.
R30.0	Dysuria	Dysuria is pain or burning when passing urine, most often from a urinary tract infection.
R31.0	Gross hematuria	Gross haematuria is blood in the urine that is visible to the naked eye.
R31.29	Other microscopic hematuria	Other microscopic haematuria is blood in the urine found on testing but not visible, other than the benign essential type.
R31.9	Hematuria, unspecified	Haematuria means blood in the urine, whether visible or microscopic; the type is not specified here.
R32	Unspecified urinary incontinence	Urinary incontinence is involuntary leakage of urine; the type is not specified here.
R33.9	Retention of urine, unspecified	Retention of urine is inability to empty the bladder; the type is not specified here.
R34	Anuria and oliguria	Anuria and oliguria mean absent or very low urine production, an important sign of kidney problems.
R35.0	Frequency of micturition	Frequency of micturition means needing to pass urine more often than usual.
R35.1	Nocturia	Nocturia is waking at night to pass urine, common with age, prostate enlargement and some medical conditions.
R35.89	Other polyuria	Other polyuria: passing abnormally large volumes of urine for reasons other than the specific polyuria codes.
R39.15	Urgency of urination	Urgency of urination is a sudden, compelling need to pass urine that is hard to postpone.
R41.0	Disorientation, unspecified	Disorientation means confusion about time, place or person; the cause is not specified here.
R41.3	Other amnesia	Amnesia is loss of memory; this code covers types other than those separately classified.
R41.82	Altered mental status, unspecified	Altered mental status is a change in awareness, alertness or thinking from a person's baseline, cause not specified.
R41.840	Attention and concentration deficit	Attention and concentration deficit means difficulty focusing or sustaining attention, recorded as a finding.
R42	Dizziness and giddiness	Dizziness and giddiness include light-headedness and vertigo-like sensations, recorded while the cause is assessed.
R45.851	Suicidal ideations	Suicidal ideations are thoughts of harming or killing oneself, recorded as a clinical finding requiring careful assessment.
R47.01	Aphasia	Aphasia is impairment of language — speaking, understanding, reading or writing — usually from brain injury such as stroke.
R47.81	Slurred speech	Slurred speech is poorly articulated speech, recorded as a symptom while the cause is assessed.
R49.0	Dysphonia	Dysphonia is a disorder of the voice, such as hoarseness or weakness of voice.
R50.9	Fever, unspecified	Fever is a raised body temperature, usually above 38°C, recorded when the cause is not yet specified.
R51.9	Headache, unspecified	Headache recorded as a symptom when a specific headache type has not been coded.
R52	Pain, unspecified	Pain recorded without a specified site or type, used when pain is documented in general terms.
R53.1	Weakness	Weakness here means a general feeling or finding of reduced strength, recorded while the cause is assessed.
R53.82	Chronic fatigue, unspecified	Chronic fatigue is long-lasting tiredness not explained by exertion; here a specific fatigue syndrome is not specified.
R53.83	Other fatigue	Other fatigue covers tiredness patterns not covered by the chronic fatigue code, a very common symptom code.
R55	Syncope and collapse	Syncope is a brief loss of consciousness (fainting) from a temporary fall in blood flow to the brain; collapse is a similar fall.
R56.9	Unspecified convulsions	Convulsions are episodes of uncontrolled shaking or stiffening, recorded without the type or cause being specified.
R59.0	Localized enlarged lymph nodes	Localised enlarged lymph nodes ('swollen glands') in one area, recorded while the cause is assessed.
R60.0	Localized edema	Localised oedema is swelling from fluid in the tissues in one area, such as one leg or one arm.
R60.1	Generalized edema	Generalised oedema is widespread swelling from fluid throughout the body, seen in heart, kidney and liver disease.
R60.9	Edema, unspecified	Oedema means swelling caused by excess fluid in the body's tissues; the pattern is not specified here.
R61	Generalized hyperhidrosis	Generalised hyperhidrosis is excessive sweating over much of the body, beyond what temperature or exercise explains.
R63.4	Abnormal weight loss	Abnormal loss of weight means unintentional weight loss, recorded while causes are investigated.
R65.20	Severe sepsis without septic shock	Severe sepsis is sepsis with organ dysfunction, here without septic shock.
R65.21	Severe sepsis with septic shock	Severe sepsis with septic shock: sepsis with organ dysfunction and blood pressure too low despite fluids.
R73.03	Prediabetes	Prediabetes means blood glucose is above normal but not yet in the diabetes range, raising future diabetes risk.
R73.9	Hyperglycemia, unspecified	Hyperglycaemia means raised blood glucose recorded as a finding, in a person not coded as having diabetes.
R74.01	Elevation of levels of liver transaminase levels	Raised liver transaminase levels (ALT/AST) on blood tests, an abnormal finding that prompts a search for liver causes.
R76.11	Nonspecific reaction to tuberculin skin test without active tuberculosis	A nonspecific reaction to the tuberculin skin test (a positive TB skin test) without any evidence of active tuberculosis.
R79.82	Elevated C-reactive protein (CRP)	A raised C-reactive protein (CRP) level, a blood marker of inflammation, recorded as an abnormal finding.
R79.89	Other specified abnormal findings of blood chemistry	Other specified abnormal findings of blood chemistry not covered by more specific result codes.
R80.1	Persistent proteinuria, unspecified	Persistent proteinuria is protein in the urine found on repeated testing; the pattern is not further specified.
R80.9	Proteinuria, unspecified	Proteinuria means protein in the urine, a key marker of kidney damage; the type is not specified here.
R87.610	Atypical squamous cells of undetermined significance on cytologic smear of cervix (ASC-US)	ASC-US means atypical squamous cells of undetermined significance on a cervical screening smear: mildly abnormal cells of uncertain meaning.
R91.1	Solitary pulmonary nodule	A solitary pulmonary nodule is a single round spot found on a lung scan, most often benign but usually followed up.
R91.8	Other nonspecific abnormal finding of lung field	Other nonspecific abnormal findings on lung imaging, such as shadowing or opacities not covered by specific codes.
R92.8	Other abnormal and inconclusive findings on diagnostic imaging of breast	Other abnormal or inconclusive findings on breast imaging (such as mammography) that need further assessment.
R94.31	Abnormal electrocardiogram [ECG] [EKG]	An abnormal electrocardiogram (ECG/EKG) is a heart tracing finding outside the expected pattern, needing clinical interpretation.
R94.4	Abnormal results of kidney function studies	Abnormal results of kidney function studies are blood or urine test results suggesting the kidneys are not working normally.
R94.5	Abnormal results of liver function studies	Abnormal results of liver function studies are blood test results suggesting liver inflammation or dysfunction.
R97.20	Elevated prostate specific antigen [PSA]	A raised PSA (prostate specific antigen) blood test result, which can occur with prostate enlargement, inflammation or cancer.

This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.

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Chapter 18: Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00–R99)

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