The document provides an introduction to SNOMED CT, which is described as the most comprehensive, multilingual clinical healthcare terminology in the world. It allows for very granular data capture and powerful analytics and decision support. The document traces the history and development of SNOMED CT and compares it to other clinical coding systems such as ICD-10, noting advantages such as having no limit on the number of codes and concepts with multiple relationships that enable more flexible querying.

1. SNOMED CT
Systematized Nomenclature Of Medicine – Clinical Terms
---An introduction ---
Dr Karanvir Singh
MBBS, MS, FRCS (Glasgow)
Chief Medical Information Office
Apollo Hospitals

2. Systematized
Nomenclature of
Pathology (SNOP)
1965 CAP
Broad clinical terms
included (SNOMED)
1975 CAP
Logic based
SNOMED-RT
2000 CAP
Read codes1980s NHS UK
Read codes v3
Clinical Terms v3
CTV3
1990s NHS UK
SNOMED-CT2007 IHTSDO
India became a member
of the IHTSDO
2014
SNOMED-CT2002
CAP
NHS UK
US UK

3. SNOMED CT

4. SNOMED CTerminology

5. Coding system vs Terminology
A 66 year old man was brought the accident and emergency
department of a trauma center hospital with a history of near drowning
in a boating accident. After initial resuscitation he was airlifted, from
the holiday resort he was staying in, by a medical helicopter. On
admission he was unconscious…

6. Coding system – ICD-10
A 66 year old man was brought the accident and emergency
department of a trauma center hospital with a history of near drowning
in a boating accident. After initial resuscitation he was airlifted, from
the holiday resort he was staying in, by a medical helicopter. On
admission he was unconscious…
Boating accident 90.1
Near drowning T75.1
Unconscious R40.2

7. Terminology – SNOMED CT
A 66 year old man was brought the accident and emergency
department of a trauma center hospital with a history of near drowning
in a boating accident. After initial resuscitation he was airlifted, from
the holiday resort he was staying in, by a medical helicopter. On
admission he was unconscious…
Man 339947000
Boating accident 43682008
Near drowning 87970004
Holiday resort 257636005
Medical helicopter 32472009
Resuscitation 439569004
Trauma center 36125001
Accident emergency 394576009
On admission 278307001
Unconscious 418107008
• No history of diabetes
• Father has cataract
• Hip replacement is planned for
next month

8. Natural language processing

9. Natural language processing

10. Snomed CT
• Is the most comprehensive, multilingual clinical healthcare
terminology in the world
• Allows very granular data capture that can be viewed at any other
level of granularity
• Allows powerful analytics & decision support

11. Snomed CT
• Is the most comprehensive, multilingual clinical healthcare
terminology in the world
• Allows very granular data capture that can be viewed at any other
level of granularity
• Allows powerful analytics & decision support

12. Snomed CT
• Is the most comprehensive, multilingual clinical healthcare
terminology in the world
• Allows very granular data capture that can be viewed at any other
level of granularity
• Allows powerful analytics & decision support

13. Snomed CT
• Is the most comprehensive, multilingual clinical healthcare
terminology in the world
• Allows very granular data capture that can be viewed at any other
level of granularity
• Allows powerful analytics & decision support

14. Snomed CT
• Is the most comprehensive, multilingual clinical healthcare
terminology in the world
• Allows very granular data capture that can be viewed at any other
level of granularity
• Allows powerful analytics & decision support
14

15. Snomed CT
• Is the most comprehensive, multilingual clinical healthcare
terminology in the world
• Allows very granular data capture that can be viewed at any other
level of granularity
• Allows powerful analytics & decision support

16. Snomed CT
• Is the most comprehensive, multilingual clinical healthcare
terminology in the world
• Allows very granular data capture that can be viewed at any other
level of granularity
• Allows powerful analytics & decision support
16

17. Let us see how it is better than existing
healthcare coding systems
Let us compare it with ICD-10
17

18. More clinical terms

19. Codes for Ectopic Pregnancy in ICD-10
• ICD-10 has five codes (terms) only
• Abdominal
• Tubal
• Ovarian
• Others
• Unspecified

20. Terms for Ectopic pregnancy in SNOMED CT
Abdominal pregnancy Membranous pregnancy
Aborted ectopic pregnancy Mesenteric pregnancy
Angular pregnancy Mesometric pregnancy
Cervical pregnancy Miscarriage of tubal ectopic pregnancy
Combined heterotopic pregnancy
Multiple pregnancy involving intrauterine pregnancy and
tubal pregnancy
Combined intrauterine and ovarian pregnancy Mural pregnancy
Combined pregnancy Ovarian pregnancy
Combined tubal and intrauterine pregnancy Rudimentary horn pregnancy
Compound ectopic Ruptured ectopic pregnancy
Cornual pregnancy Ruptured tubal pregnancy
Delivery of viable fetus in abdominal pregnancy Secondary abdominal pregnancy
Fallopian pregnancy Simultaneous intrauterine and extrauterine pregnancies
Fallopian tube pregnancy Tubal abortion
Heterotopic pregnancy Tubal pregnancy
Intraligamentous pregnancy Unruptured tubal pregnancy
Intraperitoneal pregnancy Viable fetus in abdominal pregnancy

21. Multiple ‘ancestors’

22. ICD-10 classification system has a problem
Look at how Pneumonia is classified

23. Pneumonia is all over the place!
Section Code Title
Infectious disorders B01.2 Varicella pneumonia
Infectious disorders B05.2 Measles complicated by pneumonia
Infectious disorders B20.6 HIV disease resulting in Pneumocystis carinii pneumonia
Diseases of respiratory system J10.0 Influenza with pneumonia, other influenza virus identified
Diseases of respiratory system J11.0 Influenza with pneumonia, virus not identified
Diseases of respiratory system J12 Viral pneumonia, not elsewhere classified
Diseases of respiratory system J13 Pneumonia due to Streptococcus pneumoniae
Diseases of respiratory system J14 Pneumonia due to Haemophilus influenzae
Diseases of respiratory system J15 Bacterial pneumonia, not elsewhere classified

24. Viral pneumonia
Infectious disease of
lung
Lower respiratory tract
infection
Disorder of lung
Disease
Viral infection
Infective pneumonia
Viral respiratory
infection
Viral disease
Infectious disease
Poly-hierarchy in SNOMED CT

25. ICD is running out of codes
• Since code numbers are the main stay of classification, and the
number of diseases are very large in number, ICD is running out of
codes.
• Multiple disorders are being grouped under one code

26. ICD is running out of codes
• Since code numbers are the main stay of classification, and the
number of diseases are very large in number, ICD is running out of
codes.
• Multiple disorders are being grouped under one code

27. Snomed CT has no limits on the codes that
can be used
No sharing of codes by two different conditions

28. Comparison of existing coding systems
Coding
system
ICD-10 ICD-10 PCS LOINC NANDA CPT4 SNOMED CT
Diagnosis Yes No No Partial No Yes
Procedures /
operations
No (except
pregnancy
related)
Yes No No Yes Yes
Laboratory No No Yes No No Yes
Nursing No No No Yes No Yes
Special
context (e.g
not diabetic)
No No No No No Yes
Meaning
based
analytics
No No No No No Yes

29. Will SNOMED CT replace ICD-10?
Yes & No
• Clinical modules & analytics would benefit from SNOMED CT
• The medical records departments will continue ICD-10

30. Let us look at the nuts & bolts of SNOMED CT

31. These are four different conditions (clinical ideas)
1. Ischemic heart disease
2. Angina
3. Unstable angina
4. Myocardial infarction
5. Heart attack
6. Cardiac infarction
7. MI
Same clinical meaning (idea)
Each clinical idea is called a concept

32. Each concept has a (near) random concept number
1. Ischemic heart disease 414545008
2. Angina 194828000
3. Unstable angina 4557003
4. Myocardial infarction
5. Heart attack
6. Cardiac infarction
7. MI
Same clinical meaning (idea) 22298006

33. The same concept has different translations
1. Ischemic heart disease 414545008 - cardiopatía isquémica
2. Angina 194828000 - angina de pecho
3. Unstable angina 4557003 - síndrome preinfarto
4. Myocardial infarction
5. Heart attack
6. Cardiac infarction
7. MI
Same clinical meaning (idea) 22298006 -
infarto de miocardio

34. Independent system of classification
Concept Concept ID
Ischaemic Heart Disease 414545008
Angina 194828000
Unstable Angina 4557003
Myocardial Infarction 22298006
Heart Attack 22298006
Cardiac Infarction 22298006
MI 22298006

35. In independent system of classification
Concept Concept ID
Ischaemic Heart Disease 414545008
Angina 194828000
Unstable Angina 4557003
Myocardial Infarction 22298006
Heart Attack 22298006
Cardiac Infarction 22298006
MI 22298006
Myocardial disease
Myocardial necrosis
Necrosis of an
anatomical site

36. Thus…
• Each clinical idea is a concept and has a unique concept number
• Each concept number has multiple terms for it
• In different languages…
• There is no limit on the number of concepts. Hence different
conditions do not have to share the same code
• Concepts are connected to other concepts (parents / children)
independent of their codes – multiple relationships
• There are other relationships also, defining different properties of a
concept

37. How do multiple relationships help?
Cellulitis of
foot
Disorder of
foot
Cellulitis of
lower limb
Is a child of…Is a
Understanding
the logic part
of SNOMED CT
Very powerful
analytics

38. Multiple types of relationships
Cellulitis of
foot
Disorder of
foot
Cellulitis of
lower limb
CellulitisFoot structure
Is aIs a
Associated morphologyFinding site

39. Cellulitis of
foot
Disorder of
foot
Cellulitis of
lower limb
CellulitisFoot structure
Is aIs a
Associated morphologyFinding site
Cellulitis of toe
Cellulitis of
heel
Is a
Is a

40. Cellulitis of
foot
Disorder of
foot
Cellulitis of
lower limb
CellulitisFoot structure
Is aIs a
Associated morphologyFinding site
Cellulitis of toe
Cellulitis of
heel
Is a
Is a
Toe structure
Finding
site
Cellulitis
Associated morphology
Is a

41. Cellulitis of
foot
Disorder of
foot
Cellulitis of
lower limb
CellulitisFoot structure
Is aIs a
Associated morphologyFinding site
Cellulitis of toe
Cellulitis of
heel
Is a
Is a
Toe structure
Finding
site
Heel structure
Finding
site
Cellulitis
Associated morphology
Cellulitis
Associated
morphology
Is a
Is a

42. Cellulitis of
foot
Disorder of
foot
Cellulitis of
lower limb
CellulitisFoot structure
Is aIs a
Associated morphologyFinding site
Cellulitis of toe
Cellulitis of
heel
Is a
Is a
Toe structure
Finding
site
Heel structure
Finding
site
Cellulitis
Associated morphology
Cellulitis
Associated
morphology
List me all foot problems
Is a
Is a

43. Cellulitis of
foot
Disorder of
foot
Cellulitis of
lower limb
CellulitisFoot structure
Is aIs a
Associated morphologyFinding site
Cellulitis of toe
Cellulitis of
heel
Is a
Is a
Toe structure
Finding
site
Heel structure
Finding
site
Cellulitis
Associated morphology
Cellulitis
Associated
morphology
List me all patients with cellulitis
Is a
Is a

44. Associated morphology = Cellulitis*
Cellulitis of foot
Cellulitis of foot excluding toe
Cellulitis of forearm
Cellulitis of forehead
Cellulitis of gingiva
Cellulitis of groin
Cellulitis of hand
Cellulitis of hand excluding finger
Cellulitis of head
Cellulitis of heel
Cellulitis and abscess of lower leg
Cellulitis and abscess of lower limb
Cellulitis and abscess of neck
Cellulitis and abscess of nose (external)
Cellulitis and abscess of perineum
Cellulitis and abscess of shoulder
Cellulitis and abscess of submandibular region
Cellulitis and abscess of temple region
Conditions with the word “Cellulitis” within it
*Partial data

45. Associated morphology = Cellulitis*
Cellulitis of foot
Cellulitis of foot excluding toe
Cellulitis of forearm
Cellulitis of forehead
Cellulitis of gingiva
Cellulitis of groin
Cellulitis of hand
Cellulitis of hand excluding finger
Cellulitis of head
Cellulitis of heel
Cellulitis and abscess of lower leg
Cellulitis and abscess of lower limb
Cellulitis and abscess of neck
Cellulitis and abscess of nose (external)
Cellulitis and abscess of perineum
Cellulitis and abscess of shoulder
Cellulitis and abscess of submandibular region
Cellulitis and abscess of temple region
Beat knee
Chronic recurrent streptoccocal erysipelas
Cutaneous erysipeloid
Disseminated cutaneous erysipeloid
Erysipelas
Erysipelas of lower limb
Erysipeloid
Facial erysipelas
Localized cutaneous erysipeloid
Ludwig's angina
Onychia of finger
Phlegmon
Postpartum AND/OR puerperal erysipelas
Recurrent erysipelas
Seal finger
Conditions with the word “Cellulitis” within it
Conditions even without the word “Cellulitis”
*Partial data

46. How relationships help in decision support
Pick up all cases of
cerebrovascular accident for
consideration for
thrombolytic therapy
Use it to identify
potential cohorts for
clinical trials for a new
breast cancer drug.
Warn if the patient has any type
of diabetes AND any type of
kidney disease

47. How is it used in a hospital’s EMR?

48. The hospital’s EMR software Snomed CT
Record services (EMR) Terminology services (Snomed CT)
Patient Ram Lal, age 56, admitted with a diagnosis of Herni
Hernia
Inguinal hernia
Indirect inguinal hernia
Indirect inguinal hernia with obstruction

49. Leveraging relationships
We can show all
the SubType
concepts of E in
the operation list
of a foot surgeon
Operations
on the foot

50. SubTypes (All descendants)
Operations
on the foot
Foot joint
operations
Foot
incision
Division of
muscle of
foot
Tenotomy of
abductor
hallucis muscle

51. How will clinicians benefit from it?
The drawbacks of current coding system that are addressed by SNOMED CT

52. ICD-10 has very limited search – no synonyms
• The doctor may search for any of these terms for the same diagnosis
• Renal calculus
• Renal stone
• Nephrolith
• Calculus in kidney
• Kidney stone
• Kidney calculus
• Only the term Calculus in Kidney exists in ICD-10
• Such issues are present with most diagnosis

53. No abbreviations in ICD-10
• The doctor may search by typing
• COPD
• MI
• IHD

54. ICD-10 terms are not appropriate for printing
What the doctor wants to write What is available in ICD-10 tables – prints as such
Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease, Unspecified
Ureterocele Other specified disorders of kidney and ureter
Neonatal tetanus Other tetanus
Achlorhydria Other specified diseases of stomach and duodenum
Recurrent appendicitis Other appendicitis
Indirect inguinal hernia Inguinal hernia
Direct inguinal hernia Inguinal hernia
Strangulated inguinal hernia Unilateral or unspecified inguinal hernia, with obstruction,
without gangrene
Hepatic encephalopathy Hepatic failure, not elsewhere classified
Bird flu (H5N1) Influenza due to certain identified influenza virus
Swine flu (H1N1). Influenza due to certain identified influenza virus

55. ICD-10 codes are not appropriate for printing
What the doctor wants to write What is available in ICD-10 tables – prints as such
Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease, Unspecified
Ureterocele Other specified disorders of kidney and ureter
Neonatal tetanus Other tetanus
Achlorhydria Other specified diseases of stomach and duodenum
Recurrent appendicitis Other appendicitis
Indirect inguinal hernia Inguinal hernia
Direct inguinal hernia Inguinal hernia
Strangulated inguinal hernia Unilateral or unspecified inguinal hernia, with obstruction,
without gangrene
Hepatic encephalopathy Hepatic failure, not elsewhere classified
Bird flu (H5N1) Influenza due to certain identified influenza virus
Swine flu (H1N1). Influenza due to certain identified influenza virus

56. Summary
• Snomed CT is the terminology that supports the EMR. On its own it
does nothing
• It is very clinician friendly
• It is multilingual
• It allows very powerful data analytics
• It augments decision support capabilities of an EMR