Marc
Jamoulle
ESP/ULB
Master in Public Health, 2002
Lecture on
Classification systems in Primary Care
Paper received in December 2001
from Dr Roger Weeks (Gp) (mailto:roger@safescript.org)
from Doctor's Independent Network
Published on Internet in
February 2002
Content ;
§
Background, use
by practices:,versions of read in use:,the hierarchy and read code chapters, what can be recorded about a patient?, problem orientation,
§
The diagnosis:,query diagnoses and differential diagnoses,
os and nos and nec, symptom
codes, examinations,
§
Tests and diagnostic
procedures, drugs, screening codes, monitoring
codes, 'history of’ codes, referrals, other
therapeutic procedures,
§
Social and personal history,
domiciliary services, administration, codes
preceding terms,the z chapter,
§ General guidelines, list
of chapters:term keys: shortest term and
shortest picking list, example of codes
Read codes are a comprehensive clinical coding
system which covers medical terms and procedural and administrative terms. The
codes are not limited to diagnostic and procedural codes, but also include
codes for symptoms, test results, screening, family history and many other
areas which will be described in more detail below. GP computer systems accredited
under RFA4 are expected to use Read codes. The
coding has been expanded to provide terms and codes for nursing and the
professions allied to medicine and is available in Version 3 of the codes.
Once software companies receive these codes,
they will incorporate them into their own software and make them available to
their general practice customers. The timetable for this will vary according to
each company.
Practices vary in their choice of the level and
range of information they wish to record using Read codes. Many practices have
started by inputting their repeat prescribing. Some will then concentrate upon
recording diagnostic information for the major chronic diseases. Others will
aim at recording all consultations, test results, examinations etc and in
effect be approaching the 'paperless' practice.
There are two sets of codes in use in general practice at present:: four digit codes used by Meditel and some EMIS systems and five digit codes used by other EMIS and other computer systems. Version 3 is not in general use yet. Check and update
Codes are organised in a hierarchical system
like chapters where the first digit is the chapter heading. These begin with A
to R, a to r and 1 to 9. Subheadings in each chapter give progressively more
detail, so that in Read 5 the first digit indicates the general area and
subsequent digits give greater detail.
G.... is circulatory system diseases
G3... is ischaemic heart disease
G30.. is acute MI
G300. is acute anterolateral infarct
Practices are recording different degrees of
clinical information on their computers and therefore are using the codes in
different ways. For example, many are using it to record the diagnosis of major
or common chronic diseases, while others are using their computers to record
all their consultations and are therefore using a fuller range of codes.
The following clinical information may be
recorded about a patient:
* the
initial recording of the patients' reasons for a visit and their description of
symptoms and/or symptoms identified by the doctor
* tests
performed
* a
diagnosis
* treatment
* referral
This information will not necessarily be
available in this order.
In addition to these, the practice may be
recording:
* monitoring
* preventive
procedures
* relevant
family history
Read coding allows the coding of symptoms,
physical signs, test results, therapies etc as well as diagnoses on the
clinical system. If data is recorded either as a problem heading or linked as a
problem heading, it allows data to be grouped logically and viewed more easily.
*
In general, symptoms and signs are preferred as
problem headings over diseases, unless these are established, e.g. chronic
diseases like diabetes or myxoedema.
*
Obvious diagnoses are preferred to symptoms
e.g. ‘inguinal hernia’ to ‘lump in groin’.
*
Other problem headings which are useful are:
screening, immunisations, contraception, pregnancy care, child development
exams., other preventive measures.
*
A problem heading may be changed to a disease
later if a chronic disease is diagnosed e.g. ‘polyuria’ might be changed to
‘diabetes mellitus’ if that diagnosis is established. Prostatism changed to
prostate cancer. In this case the original presenting symptom must be left on
the record.
*
Where symptom codes are offered as ‘symptom
site’ or ‘symptom character’ site is preferred and character linked to the
problem heading e.g. ‘frontal headache’ preferred to ‘shooting headache’.
In general, it is recommended that practices record
a diagnosis, where it has been made, using the diagnosis codes in chapters
A to Q. These are organised according to physiological systems e.g. codes
beginning with G. relate to the cardiovascular system, those beginning with H.
relate to the respiratory system.
Some conditions may appear in more than one
part of the Read codes system, where more than one biological system is
involved e.g. diabetes mellitus with retinopathy (C105.) and diabetic
retinopathy (F420.) or diabetes mellitus with neuropathy (C106.) and
polyneuropathy in diabetes (F372.) and this can be problematic. It may be
necessary to have a specific agreement about consistency of use of the terms
for the practice.
The date
of diagnosis should be recorded wherever possible. Specificity of this is
particularly important for more recent diagnoses when one wants to look at the
incidence of a disease and wants to know how many new diagnoses have been seen,
for example, in the last year.
However, on the whole, the further back in time
the diagnosis was made (e.g. twenty or twenty-five years ago) the less
important it is to have a very specific date. If a patient has already had a
chronic disease for some time this should be recorded with the diagnostic code
and date of onset rather than a code for 'history of' (see below).
These cannot be recorded as such in Read codes,
so symptom codes should be recorded in the searchable fields. You can also type
the query diagnosis in the free text areas so you have a clinical record for
the individual patient which will not appear in searches for diagnoses. When a
firm diagnosis is made a diagnostic code can then be used.
These are non specific codes which should on
the whole be avoided where possible where a more appropriate code exists.
OS = otherwise specified: i.e. more
information was available but there is no more specific code for it.
NOS = not otherwise specified, i.e.
there was no further information about it.
NEC = not elsewhere classified.
A higher level code should be used in
preference to NOS.
There are two types of symptom code: if a
patient presents with a symptom but there is no firm diagnosis yet, the symptom codes found in chapter 1, 16-19 and
1A-F can be used to denote this, e.g. 182. for chest pains. These codes can
be used to record symptoms reported by the patient or identified by the doctor.
The symptom can take on the status of a
diagnosis where diagnostic tests or examinations have been carried out and have
not identified a cause or diagnosis. The symptom
codes found in chapter R
(Symptoms, signs & ill-defined conditions) are intended for this purpose.
The term itself appears prefaced by a [D]
to indicate that this is effectively a diagnosis.
These are covered in chapter 2 examinations & signs which include BMI (22K..) and
blood pressure under 246.. O/E BP reading. It also covers height (229..) and
weight (22A..) under general examination of the patient (22...).
Tests are found in chapter 3 diagnostic procedures for example 32... for ECGs. Laboratory procedures are found in chapter 4; this includes cervical smear
results (4K2.. to 4K4..). X-rays are in
chapter 5.
There are codes for assessing ability in 39..
These cover feeding, grooming, bowels assessment, bladder assessment, dressing,
chair/bed transfer, toilet dependency, mobility, stairs, bathing, walking aid
use, pressure sore index value, walking distance and physical disability
assessment score.
for example: add codes
* A
GP sees a patient with blood in the urine but no pain
- creates a record with
haematuria as the problem heading
- dip stick test
confirms blood in urine
- MSU sent to lab.
* lab
returns result MSU abnormal, RBCs +++ .WBC <3 no bacterial growth
which is recorded under
the original problem
* the
patient is referred to the urologist, and the updated version of the record
used in the referral letter.
The drugs chapters run from a to s (Note: lower
case) and include vaccines (n), anaesthesia (o) and appliances(p, q & s).
These are organised to follow the BNF chapters.
When a patient has undergone a screening test
or procedure, screening codes may be used. These are found in chapter 6 preventive procedures under
68... and include adult screening, new patient screening, geriatric screening,
heart disease screening, endocrine/metabolic screening amongst others.
Example; A patient attends for
routine hypertension screening,
Ø
record using a hypertension screening code
(68B1.)
Ø
or record as 'O/E BP' code 246..
If they are
found to have raised BP
Ø
record as 'O/E BP raised' (2466), (and value if
appropriate)
But if the symptoms fulfil the criteria of diagnosed
hypertension (according to practice protocol)
Ø
record as essential hypertension (G20..)
If the patient then returns to have their blood pressure checked either
Ø
a monitoring code (662..)
Ø
or a O/E code could be used. (2...)
If a patient who has previously been diagnosed
with a particular disease is attending for monitoring of their progress, then a
monitoring code can be used (66..). A monitoring code should not be used unless
there is a diagnostic code already entered.
These are found in the preventive procedures chapter (6). This chapter also includes
contraception (61...) and immunisations (65...), child health (64...) as well
as the chronic disease monitoring codes (66...). You will find such codes as
the diabetic monitoring codes (66A..) here and the responsibility for care can
be coded in (66S..) which is the chronic disease - monitoring arrangements. In
the case of diabetes the monitoring codes relate to the type of treatment (i.e.
insulin, oral or diet) and the use of these codes is the easiest way to
distinguish between different types of diabetics.
These are best avoided unless there is a clear
reason for their use. If the patient has had a history of an acute disease, or
has had a disease in the past which has been cured and there are no sequelae
then it may be appropriate to use a history code, e.g. H/O thyroid disease
(14..). This will probably only be used rarely. However for a chronic disease,
or a disease which is likely to have recurrent episodes (e.g. asthma), a
diagnosis code should be used and the date of onset and/or last episode
recorded. Some people do use these codes for current illnesses.
Referrals are under 8H... and cover admissions,
both emergency and non-urgent; referrals to the main medical and surgical
specialties; referrals to other professions, e.g. physiotherapy, optician,
stoma nurse; arrangements for other care, e.g. home help; domiciliary visits.
These are also found in chapter 8 and include
such areas as wound dressings, tlc, therapy aids,(e.g. visual aids, appliances,
colostomy bags) physiotherapy treatment, OT and psychotherapy.
Information about the patient which is not
clinical but of can be of use to the practice, can be recorded. This is an area
which practices start considering once they have tackled the clinical information.
Mobility - social functioning is
found under 13C. and includes such
codes to describe ranges of mobility and access to transport. Housing is found under 13D. and 13E. and 13F. holds a housing dependency scale. Examples are
13F3 lives alone, no help available, 13F6 nursing or other home.
Codes for ‘milestones’ record such areas as the
personal milestones (13H..) of
marriage, battering, looking after chronic sick relative, on remand. Family milestones (13I..) cover
adoption, child on ‘at risk’ register. Employment
milestones (13J..) record retirement, left military service, unemployed. In
addition there are codes for ‘economic milestones’, family illness, family
bereavement and sickness/invalidity benefit. Examples are 13W2. aged parents,
13L1. relative - physical handicap.
These are contained in the 13G.. chapter and code such domiciliary services as district nurse
attending, health visitor, midwife, social worker, voluntary worker, home help,
meals on wheels, domiciliary chiropody and OT. These are separate codes to the
8H.. referral codes, where a service has been initiated by the practice and can
be used to record what the patient is receiving.
Chapter (9) is used for administration
recording e.g. for patient attendance at clinics. There are some useful codes
such as:
9344 notes summary on computer
9345 extensive notes on computer
9346 total notes on computer
which are useful when transferring medical
records onto the computer.
The following letters in square brackets appear
before the term itself and denote a specific type of code:
[D] where a symptom takes on the status of a
diagnosis; discussed under symptom codes.
[M] morphology codes. e.g. BB... morphology of
neoplasms which lists basal cell neoplasms (BB3..).
[SO] gives 'site of' codes using the operations
coding systems. It does not tell you what the operation is, only the site of
it, so it is not intended to be diagnostic. It is used in combination with a
diagnostic code, for example, accidental wound + site. The site of codes can be
used where a diagnostic code does not incorporate the actual site in the
description.
This lists Health Service contact factors, for
example vaccines, which duplicate codes elsewhere e.g. rubella vaccination can
be coded from two places, 65B, which does not cross reference and ZV.. which
does. They are included as they cross reference to ICD9 codes but are not recommended
for use for general practice purposes.
CONSISTENCY
It is highly desirable that codes are used
consistently so that the best use can be made of the computerised records by ensuring
that all the relevant cases are picked up when a search is made. For example
the same code (whether 68.. or 246..) should be used each time blood pressure
is taken and recorded, so that a search for e.g. how many patients have had
blood pressure taken will only need one search code. This avoids the problem of
having to identify which codes are being used for the same purpose, then having
to run searches on them all and combining results.
LEVEL OF CODING
In general it is desirable to use a more specific
code rather than a less specific code where possible, both for clinical
purposes and for statistical purposes. E.g. ‘epigastric pain’ is preferred to
‘upper abdominal pain’.
Practices will need to decide the level of
detail of coding, according to how they plan to use the information. At worst,
a less detailed code can lead to the wrong information being retrieved on
searching, for example:
O/E ptosis 2BE
O/E ptosis
absent 2BE1
O/E ptosis
present 2BE2
Here, a more detailed code should be used and searched
on so that present and absent can be differentiated.
The hierarchy lends itself to retrieving
information, in that searches for the code G3.. (G4.. in 4 digit Read) should
retrieve all those diagnoses coded as G3 (G4) as well as those below it in the
hierarchy, such as G33 (G44) angina and G30 (G41.) acute MI.
HOW TO FIND
THE CODES AND TERMS
There are several ways of finding the term you
need and as you become familiar with the way Read is organised and its common terms
you will find your own way around the system.
Not all software systems access the Read codes
in the same way so you may find that some of the following points do not apply.
In some software systems you can enter the Read
codes directly, instead of entering a description. This is useful if you are
only entering a limited list of conditions for which you have a list of codes,
as it saves time in the data entry process. However in most systems the codes
or terms are accessed through 'term keys' or key words or abbreviations.
When you want to make an entry, type in your
definition or term (whether it is a symptom, procedure or diagnosis) and a menu
or picking list will appear from which you choose the most appropriate code or
description. It is important to select the right term so that a diagnosis,
symptom or procedure is chosen, as appropriate.
In most systems you can type in a single word
or 'term key', an abbreviation, a lay term or the term itself.
Use the term
keys (these are a shortened part of a word) that are likely to find the
correct term. You will become familiar with those you use commonly and may find
that a short printed list by your computer is useful. Avoid using words or
parts of words which will give you very long picking lists e.g. FLU which not
only lists 'flu but also any word starting with FLUA, FLUO etc and numerous
drugs.
You can use common abbreviations, e.g. BP, IHD; but note that MI in some
systems has too many terms to list as it will search on any word beginning with
'mi..'. Myocardial infarction is found by using MYOC.
Lay terms are available, e.g. heart attack where you can
type in 'attack' or 'heart'.
Typing the organ
affected can lead to the correct term e.g. breast.
Use the
code itself (e.g. G30) if it is available on your system and you are
confident it is correct. It may be possible to access the code you want by
typing in a term or code which you know covers the term you want and progress
down the hierarchy until you find it.
DISEASES
A: infectious and parasitic diseases
B: neoplasms
BA in anatomical order
BB morphology of neoplasms
e.g. [M] Basal cell tumour
C: endocrine, nutritional, metabolic and immune
diseases
D: blood and blood-forming organs diseases
E: mental disorders
F: nervous system and sense organ diseases
G: circulatory system diseases
H: respiratory system diseases
I: not used
J: digestive system diseases
K: genitourinary diseases
L: pregnancy, childbirth and puerperium
diseases
M: skin and subcutaneous tissue diseases
N: musculoskeletal and connective tissue
diseases
O: not used
P: congenital anomalies
Q: perinatal diseases
R: symptoms, signs and ill defined conditions
(prefixed [D])
S: injury and poisoning
T: causes of injury and poisoning
U to Y: not used
Z: Health Service contact factors, prefixed
with [V]
DRUGS
a: gastroenterological
b: cardiovascular
c: respiratory
d: central nervous system
e: infectious diseases
f: endocrine
g: obstetric, gynaecological, urinary tract
h: malignant diseases and immunosuppressives
i: nutrition and blood
j: musculoskeletal and joints
k: eyes
l: ear, nose, oropharynx
m: skin
n: immunology and vaccines
o: anaesthesia
p: appliances and reagents
q: incontinence appliances
r: not used
s: stoma appliances
t to z: not used
OTHER RECORDING
1 this chapter holds mainly clinical
symptoms, but also has the following:
11 depth
of history which includes:
115 no significant history (useful
for e.g. "no history of allergies")
12 family
history
13 social
& personal history (includes alcohol, tobacco, exercise & such details as financial & other
background, e.g. in receipt of benefits.
16-19, 1A-1F clinical symptoms
2 examination chapter, includes BMI, BP
3 diagnostic procedures, including
disability assessment, both physical & mental.
4 laboratory procedures
5 X-ray chapter, which is to be expanded.
6 preventive procedures, including
contraception, antenatal care, birth details, child health, immunisations,
chronic disease monitoring, health promotion screening.
7 operations
8 other procedures, includes wound
dressings, bandaging, therapy, tlc, aids, physio exercises, other
rehabilitation, psychotherapy, referrals.
9 administration, includes registration,
death, maternity, contraceptives, items of service, certificates, patient
encounters, screening admin.
The Read coding and hierarchy is the same in
all types of software. However, each software company has designed its own
means of access to them, whether by using menus or picking lists and some do
not show the codes themselves. Some will employ term keys which can be used as
short cuts into the hierarchy and may be three or four letters long. (Meditel
and Meduser will use four or more letters, AMC will use three.)
If you type in four or more letters you will
always see four letters shown on the screen. However, you will sometimes need
to type in more than the four letters that appear to get a shorter or more useful
picking list. E.g. if you type in HEAR you will see terms which include HEART
as well as HEARING. If you type in HEART this should exclude the hearing terms.
The list below gives the term keys for
diagnoses and other terms used for the Needs Assessment Project. They show the
shortest possible term key which produces the shortest picking list and so some
words are longer than four letters. The term then appears in a picking list,
not always at the top and sometimes not even on the first page. You may find
your picking list varies (EMIS will bring to the top of the list, your most
commonly used terms.).
Term key Term (code) 5 digit Read codes and 4 digit Read codes
MYOC acute MI (G30) (G41)
INFAR acute MI (G30) (G41)
HEART heart attack (G30) (G41)
ATTACK attack - heart (G30) (G41)
DIABET Diabetes mellitus (C10) (C2)
MELL Diabetes mellitus (C10) (C2)
DIABETIC Diabetic monitoring
(66A) which will lead to diabetic on insulin, diet, oral control
ANGINA angina pectoris (G33) (G44)
ANGIOP translum balloon angiop coro a (7928)
CABG no such term key
ISCHAEM Ischaemic heart disease (G3) (G4)
CORO coronary artery operations (792)
FAILURE heart failure (G58) (G6A)
IHD IHD - ischaemic
heart disease (G3) (G4)
MI too
many items, no list appears
ASTH asthma (H33) (H43)
CEREB cerebrovascular disease (G6) (G7)
CVA CVA unspecified (G66)
TIA Transient ischaemic attack
(G65) (G74)
TRANSI Transient cerebral ischaemia (G65) (G75)
HEMIP hemiparesis (F22)
hemiplegia (F22)
SPEE speech problem (1B9)
HYPERTE hypertensive disease (G2) (G31)
BP O/E
BP reading (246)
ADVI advice to patient - subject (679)
MENT mental disorders (E)
SCHIZ schizophrenic disorders (E10) (E21)
MANIC manic psychoses (E11) (E22z)
DEPRESSI depressive psychoses (E11) (E222)
AFFE affective psychoses
(E11) (E222)
PSYC non-organic psychoses (E1) (E2)
SUIC attempted suicide (TK) (Q61)
ATTEM attempted suicide (TK) (Q61)
DEME senile/presenile dementia (E00) (E11)
SENI senile dementia
(E00) (E11)
PRESEN presenile dementia (E001)
CONFU O/E confused (2232)
CARE not useful
MEMO mild memory disturbance (E2A10)
(E4J3)
ALON lives alone, help available (13F2)
lives alone, help not available (13F3)
SOCIAL social history (13)
leads to housing dependency scale (13F)
PERSON personal history (13)
leads to housing dependency scale (13F)
HISTORY social history (13)
leads to housing dependency scale (13F)
(as
retrieved for an exercise on
coding systems during the Euro-Med-Data project)
Codes for Herpes Zoster
NHS
Clinical Terms (Read Codes) version 3 from CLUE [1]
software
XE2x9
Herpes zoster infection
X70JF
Thoracic herpes zoster infection
X70JG
Lumbar herpes zoster infection
X009c
Acute trigeminal herpes zoster
X20RH
Herpes zoster infection of oral mucosa
X00mI Acute herpes zoster pharyngitis
F5016 Geniculate herpes zoster
X0016
Herpes zoster encephalitis
X70JN
Multidermatomal herpes zoster infection
A5321
Herpes zoster with keratoconjunctivitis
A5322
Herpes zoster iridocyclitis
Read
Version 1 and 2 provided by Roger Weeks from DIN[2]
Version1 Version2
Herpes zoster |A44.. |A53..
|Herpes zoster -Shingles
Post-herpetic
neuralgia |A441. |A531.|Herpes zoster with other central nervous system
complication
Ophthalmic herpes zoster |A442. |A532.|Herpes
zoster with ophthalmic complication
Ramsay-Hunt
syndrome |A443. |A53x.|Herpes zoster with other specified complication
Other herpes zoster A44Z. |A53z.|Herpes zoster NOS
[1]
CIC Look Up Engine (CLUE), CLUE Browser for NHS CTV3, Version: 2.0.0021, March
2000 Clinical Information
Consultancy http://www.clinical-info.co.uk
[2] Added by Roger
Weeks from Doctors' Independent Network
http://www.compudata.co.uk/din.html
http://www.ulb.ac.be/esp/mfsp/readcodes.htm