Classifying and Coding Causes of Sickness Absence

  1. Introduction
  2. Using the system
  3. Step 1 - Allocating level 1 classification code
  4. Step 2 - Allocating level 2 classification code
  5. Notes and exceptions
  6. Link here to the full level 1 and 2 coding list page


As part of the development programme for SART the IOM, in collaboration with HSE, was asked to devise a suitable standardised scheme for the classification and coding of Sickness absence causes. Aims were to produce a simple, yet sufficiently comprehensive scheme, with links to other existing medical classifications. The purpose of this guidance note is to describe the coding system that was produced and to outline how it can be used to record sickness absence cause in the SART, or utilised in other systems.

The classification scheme is designed to allow employers to easily classify in a standardised way the reasons for sickness absence provided by employees, be they from from verbal reports, self-certificates or from a medical practitioner via a medical certificate.

There are two levels of coding within the scheme:

In the SART it is mandatory to choose a level one category; the selection of a level two category is strongly recommended, but optional.

The scheme has been devised to be broadly compatible with the internationally recognised ICD (International Classification of Disease) scheme at the top level, so as to enable the comparison of rates in future particularly with information gathered at a local level and used to influence planning of health and related services.

Using the system:

In the SART system a full classification of sickness absence cause is represented by a 5 digit numeric code:

The first two digits of the code represent the level one category, and they range from 10 to 33. "Other known causes (nec) - not elsewhere classified" are coded as 98 and "Unknown causes/Not specified" are coded as 99. The last three digits are used for the more specific level two cause of absence.

In the interests of producing a compact system, whilst at the same time seeking compatibility with other medical coding schemes, not every possible specific cause can be made available at level two. However, it is envisaged that periodically the classification and coding scheme will be updated using suggestions and information returned by users and reviewers of the scheme.

The full two-level classification scheme can be viewed here: saclist.htm

In the SART the cause for each episode of sickness absence should firstly be recorded using the level one classification codes and, if possible by also allocating a level two classification code (wherever possible, the allocation of a second level code is strongly advocated). Instructions in the use of the scheme for  the sickness absence recording screens of SART is given here.

Step1 - Cause Level 1 classification:

  1. Identify the relevant code from the level 1 code list. This can be done by using the drop-down list available, or by using the search (binoculars) icon to find and allocate a code. The level one code will usually be related to the body system involved, but there are some exceptions (but see notes for exceptions below), for example Skin problems, Back pain, Chest and Respiratory problems.
  2. If a general absence cause is provided, but it is not sufficiently detailed to allow a proper level 1 classification, then this should be allocated to code 98, 'other known causes (nec) - not elsewhere classified'. Examples of this could be where illness is described as 'malaise' or 'feeling poorly', etc.
  3. If no absence cause is given, or the cause is reported to be unknown, then this should be recorded as code 99, 'Unknown causes - not specified'.

Step 2 - Cause Level 2 classification:

  1. Having allocated a level 1 code, only level 2 codes that pertain to the level 1 code will be available - For example, if 'back pain' has been entered at level 1, only more detailed back pain causes will be available at level 2. If the search function was used to allocate a code in Step 1, this will at the same time have allocated a level 2 code.
  2. If the absence cause provided is not detailed enough to allow level 2 classification, this should be allocated at level 2 as 'not specified'. For example, a cause of 'skin disorder', with no further details available, would be classified at level 1 as 'skin disorder' and at level 2 as 'not specified'.
  3. If the absence cause provided allowed level 1 classification but the more detailed cause is not listed in the level 2 classification, this should be recorded as ' other' and the notes field should be used to describe the specific cause. These notes will be used to update the coding scheme in later versions of the sickness-absence recording system

The full two-level classification scheme can be viewed here: saclist.htm

Notes and exceptions:

  1. All absences due to benign and malignant growths and cancers should be allocated to "Benign and malignant growths and cancers" and not to the part of the body affected.
  2. All absences due to injuries should be allocated to "Injury/fracture" and not to the part of the body affected.
  3. All absences due to surgery should be allocated to the part of the body affected.
  4. All ear, nose, throat and eye infections should be allocated to the part of the body affected, and not to infectious diseases.
  5. All "urinary tract infections, "bladder infections" and "kidney infections" should be allocated to "Genitourinary and gynaecological disorders" unless these occur during pregnancy, in which case these should be allocated to "Pregnancy related disorders".
  6. All absences due to viruses and viral infections should be allocated to "infectious diseases".

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