ICD-10 (International Classification of Diseases, 10th Revision) coding is mandatory for Indian hospitals under NABH accreditation, PMJAY insurance claims, and ABDM health records. Wrong ICD-10 codes are the third most common reason for insurance claim rejections. This guide explains how ICD-10 works, provides 50+ common codes by specialty, and shows how to integrate coding into your HMS.

What is ICD-10 and Why Does India Use It?

ICD-10 is the World Health Organization's (WHO) international standard for classifying diseases, injuries, and health conditions. India adopted ICD-10 as the official disease classification system through:

NABH accreditation: NABH mandates ICD-10 coding as part of the IMS (Information Management System) chapter — Chapter 10 of NABH standards
PMJAY/Ayushman Bharat: All PMJAY claims must include ICD-10 diagnosis codes — wrong codes lead to rejection
Health insurance claims: All TPA and insurance claims require ICD-10 codes for processing
ABDM health records: FHIR-based digital health records use ICD-10 for diagnosis encoding — mandatory for ABHA-linked records
Hospital MIS: Disease-wise reporting and epidemiological analysis require standardised coding

ICD-10 Code Structure — How to Read a Code

Every ICD-10 code follows a structured format: Letter + 2 digits + decimal + up to 4 more characters

A00–B99: Certain infectious and parasitic diseases
C00–D48: Neoplasms (cancers and tumours)
D50–D89: Blood diseases and immune disorders
E00–E90: Endocrine, nutritional and metabolic diseases
F00–F99: Mental and behavioural disorders
G00–G99: Diseases of the nervous system
H00–H59: Diseases of the eye
H60–H95: Diseases of the ear
I00–I99: Diseases of the circulatory system
J00–J99: Diseases of the respiratory system
K00–K93: Diseases of the digestive system
M00–M99: Musculoskeletal diseases
N00–N99: Genitourinary diseases
O00–O99: Pregnancy, childbirth and puerperium
S00–T98: Injuries and external causes

Reading a Code: Example

I21.0 = I (circulatory system) + 21 (acute MI) + .0 (anterior wall) = Acute transmural myocardial infarction of anterior wall

J18.9 = J (respiratory) + 18 (pneumonia) + .9 (unspecified organism) = Pneumonia, unspecified

50 Common ICD-10 Codes for Indian Hospitals

Cardiology

I10 — Essential (primary) hypertension
I11.9 — Hypertensive heart disease without heart failure
I20.9 — Angina pectoris, unspecified
I21.9 — Acute myocardial infarction, unspecified
I25.10 — Atherosclerotic heart disease of native coronary artery (CAD)
I48.91 — Unspecified atrial fibrillation
I50.9 — Heart failure, unspecified (CCF)
I63.9 — Cerebral infarction, unspecified (ischaemic stroke)

Endocrinology / Diabetology

E11.9 — Type 2 diabetes mellitus without complications
E11.65 — Type 2 DM with hyperglycaemia
E11.40 — Type 2 DM with diabetic neuropathy, unspecified
E11.311 — Type 2 DM with unspecified diabetic retinopathy with macular oedema
E10.9 — Type 1 diabetes mellitus without complications
E05.90 — Thyrotoxicosis, unspecified without thyrotoxic crisis
E03.9 — Hypothyroidism, unspecified

Respiratory / Pulmonology

J18.9 — Pneumonia, unspecified organism
J44.1 — COPD with acute exacerbation
J45.909 — Unspecified asthma, uncomplicated
A15.0 — Tuberculosis of lung, confirmed by sputum microscopy
J96.00 — Acute respiratory failure, unspecified
J12.89 — Other viral pneumonia (including COVID-19 pneumonia)

Gastroenterology

K35.80 — Acute appendicitis without abscess
K80.20 — Calculus of gallbladder without cholecystitis
K57.30 — Diverticulosis of large intestine without perforation
K92.1 — Melaena (upper GI bleed)
K70.10 — Alcoholic hepatitis without ascites
K74.60 — Cirrhosis of liver, unspecified

Orthopaedics

M16.11 — Unilateral primary osteoarthritis, right hip
M17.11 — Primary osteoarthritis, right knee
M54.5 — Low back pain
M47.816 — Spondylosis with radiculopathy, lumbar region
S72.001A — Fracture of unspecified part of neck of right femur (hip fracture)
S42.201A — Unspecified fracture of upper end of right humerus

Obstetrics and Gynaecology

O80 — Normal delivery (spontaneous vertex)
O82.0 — Delivery by elective caesarean section (LSCS)
O14.00 — Mild to moderate pre-eclampsia, unspecified trimester
O24.419 — Gestational diabetes mellitus in pregnancy
N83.20 — Unspecified ovarian cysts
N80.0 — Endometriosis of uterus

Nephrology / Urology

N18.3 — Chronic kidney disease, stage 3
N18.6 — End stage renal disease (on dialysis)
N20.0 — Calculus of kidney (renal stones)
N39.0 — Urinary tract infection, site not specified

Neurology

G40.909 — Epilepsy, unspecified, not intractable, without status epilepticus
G43.909 — Migraine, unspecified, not intractable, without status migrainosus
G30.9 — Alzheimer's disease, unspecified
G20 — Parkinson's disease

ICD-10 Coding Mistakes That Get Claims Rejected

Using unspecified codes when specific codes exist: Coding J44.9 (COPD unspecified) when clinical notes clearly document J44.1 (COPD with acute exacerbation) — results in lower reimbursement or query
Principal diagnosis error: The condition chiefly responsible for admission must be the primary ICD-10 code. Comorbidities are secondary codes.
Not using combination codes: ICD-10 has combination codes for conditions with manifestations (e.g., E11.311 for DM with retinopathy). Using two separate codes instead is incorrect.
Outdated code book: ICD-10 codes are updated annually. Using superseded codes leads to rejection. Always use October 2025 edition codes.
Missing laterality: For paired organs (eye, ear, kidney, limb), the laterality code must be specified.
Not coding to highest specificity: For fractures, always code the encounter type (A=initial, D=subsequent, S=sequela) and displacement status.

How to Implement ICD-10 Coding in Your Hospital

Option 1: HMS with Built-In ICD-10 Database

The most efficient approach is integrating ICD-10 coding into your hospital management system. Look for:

Searchable ICD-10 database (search by keyword or code)
AI suggestions based on diagnosis text entered by doctor
Automatic pre-population of codes from discharge summary
Validation alerts for common coding errors
Mapping to procedure codes (ICD-10-PCS for procedures)

Option 2: Dedicated Medical Coding Team

Hire trained medical coders (CPC or CCS certified)
Coders review discharge summaries and assign codes retrospectively
Suitable for hospitals with 50+ IPD admissions/month
Cost: ₹25,000–₹50,000/month per coder (or outsource at ₹50–200 per case)

Option 3: Train Doctors and Nursing Staff

Provide ICD-10 training to medical officers and ward staff
Use quick-reference cards for top 20 codes in each department
Monthly audit of coding accuracy vs. clinical documentation

NABH ICD-10 Requirements

Under NABH standards (IMS chapter), hospitals must:

Use ICD-10 for all inpatient diagnosis coding
Maintain an ICD-10 coded discharge summary for all IPD patients
Generate disease-wise statistics using ICD codes (monthly MIS)
Audit coding accuracy quarterly
Use coded data for quality improvement and NABH indicator reporting

For a complete list of NABH documentation requirements, see our NABH documentation checklist.

ICD-10 vs ICD-11 — What Indian Hospitals Need to Know

WHO released ICD-11 in 2022. India has not yet mandated ICD-11 for hospital use. As of 2026:

ICD-10 remains the mandatory standard for NABH, PMJAY, and insurance claims in India
ABDM is adopting SNOMED CT alongside ICD-10 for granular clinical coding
NHA (National Health Authority) has indicated ICD-11 transition planning is underway but no mandate date announced
Hospitals should monitor NHA circulars for ICD-11 transition guidance

Conclusion

ICD-10 coding is no longer optional for Indian hospitals — it is a prerequisite for insurance billing, NABH accreditation, and ABDM compliance. The most efficient path is to choose an HMS platform with a built-in ICD-10 database and AI-assisted coding, removing the need for manual code lookup. Pair this with trained coders for complex cases and quarterly audits to maintain billing accuracy.

ICD-10 Coding Guide for Indian Hospitals (2026): How It Works and 50 Common Codes