This presentation deals with the basics of SNOMED CT with respect to it being a code for computer systems to interpret medical knowledge and initiate action. This is explained specifically with the medical professionals in mind. It begins by discussing what SNOMED CT actually is and then moving on to demonstrate how the code system can be used to merge clinical documents written in different languages into one as well as how it can help in automating repetitive tasks using an if-then-else rules engine.

1. BASICS OF SNOMED CT
FOR MEDICAL
PROFESSIONALSDr SB Bhattacharyya
MBBS, MBA, FCGP
Member, National EHR Standardisation Committee, MoH&FW, GoI
Member, IMA Standing Committee for IT, IMA Headquarters
Member, Health Informatics Sectional Committee, MHD 17, BIS
President (2010 – 2011), IAMI

2. What exactly is SNOMED CT?
SNOMED CT is a set of clinical concept codes generated by applying
its Concept Model rules (Description Logics) to the concept
definitions and inter-relationships (ontology) that can be used by
computer systems for interpreting them
Dr SB Bhattacharyya© 2
NB: This is NOT a definition, but an explanation

3. Underlying principles…
■ Medical knowledge exists
amongst its many terms
■ Using principles enumerated
in linguistics it is possible to
relate terms to concepts
■ Using principles enumerated
in computer science it is
possible to code concepts to
help machines understand
them
■ Using these principles it is
possible for humans to codify
medical knowledge in a manner
that makes it processable by
computer systems
■ This permits the systems to
“infer" the medical knowledge
Dr SB Bhattacharyya© 3

4. Why SNOMED CT
■ Medical knowledge is made concepts-based by mapping medical
terms to their corresponding concepts using the principles of
semasiology (terminology)
■ The principles of computer and information science are then applied
to define the concepts using other concepts through ontology
(specification of conceptualisation – Thomas Robert “Tom” Gruber)
■ These ontologies are then codified using Description Logics (formal
concept definitions and relations – SNOMED CT concept model)
Dr SB Bhattacharyya© 4

5. What does SNOMED CT contain?
■ The actual “codes” are the pre-coordinated or post-coordinated
expressions that help define the concepts and their inter-
relationships using machine-processable numbers to enable
computer systems to “comprehend” them
■ Human-readable terms are provided to help identify the concepts
to humans
Dr SB Bhattacharyya© 5

6. How SNOMED CT helps medical
professionals?
■ Recording clinical observations
■ Querying health records for information
■ Deriving medical knowledge from clinical documents
■ Automating repetitive jobs like posting orders thereby improving
efficiency and productivity (more time for care providers to do what
they are supposed to and specially trained to do – provide care)
■ Raising rules-based alerts and warnings to help reduce errors
Dr SB Bhattacharyya© 6

7. Role of SNOMED CT in Clinical
Documents
■ In any record, the author enters his thoughts that he has about an item
■ When a care provider enters a complaint or a physical exam finding or
a disease, he enters his thoughts about it
■ Concepts are thoughts and the recorded clinical information represents
the clinical concepts of the person making the record
■ Using SNOMED CT concepts, it is possible to code any clinical thought
about any medicine-related matter
■ These codes can then be interpreted with sufficient precision by
computer systems and acted upon as necessary
Dr SB Bhattacharyya© 7

8. SEMANTICALLY
MERGING DATA
How does SNOMED CT help?
Example 1
Dr SB Bhattacharyya© 8

9. Disclaimers for the following slides used to
demonstrate SNOMED CT’s capabilities…
■ All cases are FICTITIOUS and any resemblance to real life is purely
coincidental and totally unintentional
■ The Hindi version of records has been specially prepared by the
author for illustrative purposes only – as of mid-2017 SNOMED CT is
NOT available in that language
■ The treatment plans used in the following slides have made only to
illustrate the process and is not meant to be used as a
recommendation of any kind
Dr SB Bhattacharyya© 9

10. The case…
Mr Wilfred, a resident of the historic city of Leicester in UK is an old age
pensioner. Frequently fed up with the gloomy dreary rainy weather that is the
norm in dear old England, he escapes once a year to somewhere nice for a bit
of fun and frolic in places with better climes. He fell ill and sought treatment
from his regular GP in England in 2015. The next year, while basking on the
sea shores of sunny Spain, he fell ill again for which he sought treatment
from a local doctor over there. The year next, on his trip to view the Taj on a
full moon night in exotic India, he fell ill yet again for which he sought
treatment from a local doctor over there. On his current trip to Las Vegas in
US of A, he fell ill yet again causing him to visit the ER department of a
hospital located downtown. The doctor decided to review his previous
records. What he found is provided in the next few slides…
Dr SB Bhattacharyya© 10

11. The Records (as originally entered by the
doctors)…
Item Record # 1 Record # 2 Record # 3
Date & Time 18 June 2014, 11:05:00 21 October 2015,
10:30:00
21 April 2016, 12:15:00
Location Leicester, UK Marbella, Spain Agra, India
Chief
Complaint
Common cold Tos con fiebre सिरददद की सिकायत
Past History Appendicectomy - -
Physical
Examination
O/E - pharynx
hyperaemic
Al examen: ruidos
respiratorios normales
कोई अिामान्यता नहीीं समली
- परीक्षा पररणाम
Investigations Normal Sin particularidades िाधारण
Treatment Antihistamine Agente antitusivo
गैर-अफीओइड दददनािक
दवा
The Hindi version created by using Google Translation is used here only for illustrative purposes.
It does NOT exist as of mid-2017. The Spanish version, however, does…
Dr SB Bhattacharyya© 11

12. The Records (as available to the system
internally)…
Item Record # 1 Record # 2 Record # 3
Date & Time 18 June 2014, 11:05:00
21 October 2015,
10:30:00
21 April 2016, 12:15:00
Location Leicester, UK Marbella, Spain Agra, India
Chief
Complaint
82272006 135883003 272027003
Past History 80146002 - -
Physical
Examination
268982000 162950006 282332003
Investigations 17621005 17621005 17621005
Treatment 6425004 372791003 322208004
Dr SB Bhattacharyya© 12
Only the clinical aspects of the information has been coded using SNOMED CT here

13. The Records (as available to the ER
doctor in Las Vegas, USA)…
Item Record # 1 Record # 2 Record # 3
Date & Time 18 June 2014, 11:05:00
21 October 2015,
10:30:00
21 April 2016, 12:15:00
Location Leicester, UK Marbella, Spain Agra, India
Chief
Complaint
Common cold Cough with fever C/O - a headache
Past History Appendectomy - -
Physical
Examination
O/E - pharynx
hyperaemic
O/E - breath sounds
normal
No abnormality
detected - examination
result
Investigations Normal Normal Normal
Treatment Antihistamine Cough suppressants Non-opioid analgesics
Dr SB Bhattacharyya© 13

14. Discussion
■ When a user records using the set of available terms in any available
preferred language / dialect (in the example, English, Spanish and
Hindi), the SNOMED CT codes are stored for future use
■ When that recorded data is exchanged with an external system, the
codes are made available to that system
■ Using them, the other system can map them back to the set of available
terms in the preferred language / dialect
– In the example used, appendicectomy was the term entered by the
doctor in the UK and appendectomy was the term read by the
doctor in the US [refer back to slide #s 11 & 13 to re-check]
■ This makes it possible for any record to be viewed in a language of
one’s choice provided SNOMED CT is used and the terms that identify
the concepts are available in the desired language / dialect
Dr SB Bhattacharyya© 14

15. AUTOMATION
How does SNOMED CT help?
Example 2
Dr SB Bhattacharyya© 15

16. Ordering Rules
■ If the disorder is appendicitis
then
– Admit the patient in
hospital
– Start continuous infusion of
dextrose saline
– Perform
■ a complete blood count
■ an ultrasound scan of
abdomen
■ If disorder is acute appendicitis
then additionally post patient for
– Laparoscopic emergency
appendectomy
■ If disorder is chronic appendicitis
then additionally post patient for
– Laparoscopic appendectomy
■ If disorder is subacute appendicitis
then additionally start
– Cefoxitin sodium 2g injection
Dr SB Bhattacharyya© 16
These rules are for illustrative purposes only, not meant for actual treatment recommendations

17. “Code” for Appendicitis
Definition
■ Its SNOMED CT code (pre-coordinated expression) is
74400008 | appendicitis |
■ In machine-processable form this is
=== 18526009 + 302168000 : {116676008 = 23583003, 363698007
= 66754008}
■ In human readable form this
is a disorder of appendix (disorder) and inflammation of large
intestine (disorder) and has the attributes associated morphology
(attribute) of inflammation (morphologic abnormality) and finding
site (attribute) of appendix structure (body structure)
Dr SB Bhattacharyya© 17

18. “Code” for Appendicitis
| is a | relationships (graphical)
Dr SB Bhattacharyya© 18
Screenshot from ClinClue Xplore®

19. “Code” for acute appendicitis
■ Its SNOMED CT code (pre-coordinated expression) is
85189001 | acute appendicitis |
■ In machine-processable form this is
=== 74400008 : {116676008 = 4532008, 363698007 = 66754008}
■ In human readable form this
is a(n) appendicitis (disorder) and has the attributes associated
morphology (attribute) of acute inflammation (morphologic
abnormality) and finding site (attribute) of appendix structure
(body structure)
Dr SB Bhattacharyya© 19

20. “Code” for chronic appendicitis
■ Its SNOMED CT code (pre-coordinated expression) is
58997001 | chronic appendicitis |
■ In machine-processable form this is
=== 74400008 : {116676008 = 84499006, 363698007 = 66754008}
■ In human readable form this
is a(n) appendicitis (disorder) and has the attributes associated
morphology (attribute) of chronic inflammation (morphologic
abnormality) and finding site (attribute) of appendix structure
(body structure)
Dr SB Bhattacharyya© 20

21. “Code” for subacute appendicitis
■ Its SNOMED CT code (pre-coordinated expression) is
9124008 | subacute appendicitis |
■ In machine-processable form this is
=== 74400008 : {116676008 = 75889009, 363698007 = 66754008}
■ In human readable form this
is a(n) appendicitis (disorder) and has the attributes associated
morphology (attribute) of acute and chronic inflammation
(morphologic abnormality) and finding site (attribute) of appendix
structure (body structure)
Dr SB Bhattacharyya© 21

22. “Code” for bacterial gastroenteritis
■ Its SNOMED CT code (pre-coordinated expression) is
274080003 | bacterial gastroenteritis |
■ In machine-processable form this is
=== 128999004 + 312121001 : {116676008 = 23583003, 246075003 =
409822003, 363698007 = 122865005, 370135005 = 441862004}
■ In human readable form this
is a(n) inflammatory disorder of digestive tract (disorder) and a
bacterial gastrointestinal infectious disease (disorder) and has the
attributes associated morphology (attribute) of inflammation
(morphologic abnormality) and causative agent (attribute) of
superkingdom bacteria (organism) and finding site (attribute) of
gastrointestinal tract structure (body structure) and pathological
process (attribute) is infectious process (qualifier value)
Dr SB Bhattacharyya© 22

23. Managing Treatment Plan (machine
version)
■ If 74400008 is present as a record entry or in the definition of a
record entry then order 32485007 and 313419007 and 26604007
and 45036003 else do nothing
■ If 85189001 then also order 174041007
■ If 58997001 then also order 6025007
■ If 9124008 then also order 374159006
■ If NOT 74400008 or NOT 85189001 or NOT 58997001 or NOT
9124008 then do NOTHING
Dr SB Bhattacharyya© 23
Note the coloured arrows in slide #s 17, 19, 20 & 21

24. Managing Treatment Plan (human version)
■ If appendicitis is present in the record entry or in the definition of a
record entry then order hospital admission and continuous infusion of
dextrose saline and complete blood count and ultrasonography of
abdomen
■ If acute appendicitis then additionally order laparoscopic emergency
appendectomy
■ If chronic appendicitis then additionally order laparoscopic
appendicectomy
■ If subacute appendicitis then additionally order cefoxitin sodium 2g
injection solution 50mL bag
■ If not appendicitis or not acute appendicitis or not chronic appendicitis
or not subacute appendicitis then do NOTHING
Dr SB Bhattacharyya© 24

25. Action based on entry
■ Acute appendicitis
– Is a(n) appendicitis, so order all items related to appendicitis 
order hospital admission and continuous infusion of dextrose saline
and complete blood count and ultrasound of abdomen
– Additionally, post the patient for laparoscopic emergency
appendicectomy
■ Chronic appendicitis
– Is a(n) appendicitis, so order all items related to appendicitis 
order hospital admission and continuous infusion of dextrose saline
and complete blood count and ultrasound of abdomen
– Additionally, post the patient for laparoscopic appendicectomy
Dr SB Bhattacharyya© 25

26. Action based on entry
■ Subacute appendicitis
– Is a appendicitis, so order all items related to appendicitis  order
hospital admission and continuous infusion of dextrose saline and
complete blood count and ultrasound of abdomen
– Additionally, order cefoxitin sodium 2g injection solution 50mL bag
■ Bacterial gastroenteritis
– Is not appendicitis, so do nothing
Dr SB Bhattacharyya© 26

27. Using SNOMED CT Concept Model for
automation
Based on what is entered, the system is automatically able to post the
correct orders by accurately distinguishing between the concepts
Dr SB Bhattacharyya© 27

28. Using SNOMED CT Concept Model for
automation
■ In the example before, appendicitis was the broader form and
acute/chronic/subacute appendicitis its granular form of the
concept inflammation of large intestine
■ Although both appendicitis and bacterial gastroenteritis have the
concept inflammatory disorder of digestive tract as their supertype
ancestor, the former and latter are not inter-related, which makes it
possible for them to be handled differently using appropriate rules
Dr SB Bhattacharyya© 28

29. sbbhattacharyya@gmail.com
Dr SB Bhattacharyya© 29

30. Dr SB Bhattacharyya© 30
Thanks!