Information about NMDS clinical code tables

This document provides background and explanation to the information contained in the National Minimum Dataset (NMDS) Clinical Code Table.

The code table contains International Statistical Classification of Diseases and Related Health Problems codes for all ICD-10-AM editions, including Medicare Benefits (MBS-Extended) procedure codes. This classification is now used in New Zealand for all secondary care events.

The clinical code tables for ICD-10-AM 1st, 2nd, 3rd and 6th Editions are not available through this web site, although the documentation below relates directly to them. For code table inquiries please email the Coding Helpdesk.

All fields in this table are listed below, by their actual column name and description. The name the field may have previously been listed under is displayed in brackets. Note that there has been no change to the structure of this table, the actual naming of the fields, or the intended meaning of the field attributes. This list has just been expanded for completeness, information accuracy and consistency, and should have no effect on viewers or their systems.

Fields in the Clinical Code table

clinical_code (CLINCODE)
This column contains ICD-10-AM disease, injury, external cause, morphology and MBS-Extended procedure codes. Each code is unique when used in combination with the clinical_code_type field. National Collections reference number A0124.

clinical_code_type (CCTYP)
This field shows the clinical code table type associated with each clinical code value. It indicates which section of the ICD classification each code belongs to. The NMDS Data Dictionary includes a list of valid clinical code table types and their descriptions. National Collections reference number A0125.

clinical_code_system (SYS)
This field identifies the edition of the International Statistical Classification of diseases and Health Related Problems –ICD-10-AM – to which each code belongs. The valid clinical code system values are listed in the Clinical Coding System code table.

clinical_code_description (DESCRSHRT)
The clinical code text description; this is 100 characters wide.

death_flag (DEATH)
A flag indicating which codes are likely to be a cause of death.
If the event end type (discharge type) code on an event record is ‘DD’ (died), then the record must contain at least one diagnosis code for which the death flag in the code table has the value of ‘Y’.

gender_flag (SEX)
A flag indicating which sex is appropriate for each code.
If the gender_flag for a diagnosis in the code table is ‘B’, then an event record may contain either ‘M’ or ‘F’ or ‘U’ (unknown) or ‘I’ (indeterminate) in the sex type field. Otherwise, the sex type code on the event record must correspond to the value of the gender_flag in the code table.

low_age (LOWAGE)
An age below which a disease or procedure is not expected to be reported.
If the calculated age at discharge for an event record is lower than the value in the low_age flag then a warning message is issued.

high_age (HIGHAGE)
An age above which a disease or procedure is not expected to be reported.
If the calculated age at discharge for an event record is higher than the value in the high_age flag then a warning message is issued.

normal_nz_flag (NZNORM)
A flag indicating whether a diagnosis is likely to occur in New Zealand.
If the normal_nz_flag against a code in the code table is ‘N’ then a warning message will be generated if the diagnosis code is found in an event record.

external_cause_flag (EXTCAUSE)
A flag indicating that an external cause code is also required to describe the circumstances of injury.
If the external_cause_flag for a diagnosis is set to ‘Y’ in the code table then there must be an external cause code present in the event record.

unacceptable_diagnosis_flag (NONPDX)
A flag indicating that the code should not be used as the principal diagnosis.
If the principal diagnosis for an event is a code for which the unacceptable_diagnosis_flag is set to ‘Y’ then a warning message will be issued.

nonspecific_diagnosis_flag
A flag indicating that the code is not specific enough for primary diagnosis, and more information is needed about the diagnosis.

operation_flag (OPFLG)
A flag indicating whether an operation date is required for an operation/procedure.
If the operation_flag is set to ‘Y’ in the code table then an operation date does not have to be provided for these procedures. If the operation_flag is set to ‘N’ in the code table then an operation date must be present.

collection_type
A grouping flag, used for data analysis. A list of collection types and their descriptions is available from National Collections on request.

dagger_asterisk
A grouping flag, primarily relevant for ICD-9-CM-A only.
A dagger denotes a code describing the aetiology or underlying cause of a disease, and should always be assigned together with the manifestation code. It is represented by a ‘1’ in the field.
An asterisk denotes a code describing the manifestation of a disease and should always be assigned together with the appropriate aetiology code. It is represented by a ‘2’ in the field.

category (CAT)
A code that groups ICD codes together at the 3-digit level. All codes have category numbers except for procedure codes. A list of category codes and their descriptions (for all ICD-10-AM editions) is available from National Collections on request.

sub_category (SUBCAT)
A sub-category code that groups diagnosis codes together at the 4-digit level. All codes have sub-category numbers except for procedure codes. A list of sub-category codes and their descriptions is available from National Collections on request.

block (BLOCK)
The block number is a 4-digit code that groups procedure codes together. This is a new field for ICD-10-AM that was not in ICD-9-CM-A. Procedure codes in the coding books are organised on an anatomical basis, causing the procedure code number to not be in sequential order. To facilitate location of a procedure code this additional numbering system has been introduced. Each procedure code has an associated block number. One block number relates to one or more procedure codes. A list of block numbers and their descriptions is available from National Collections on request.

Only procedure codes (clinical code table type = O) have block numbers. This column is blank for other types of codes.

chapter
These are the chapter headings in the ICD classifications manuals, used for grouping purposes. All clinical codes except procedures (types O or M) have a chapter value. A list of chapter values and their descriptions is available from National Collections on request.

sub_chapter
These are the sub-chapter headings in the ICD classifications manuals, used for grouping purposes. All clinical codes except procedures (types O or M) have a sub-chapter value.

code_start_date
The code_start_date is an indicator value, representing the date from which the clinical code became effective. This field has been present and populated since the introduction of the ICD-10 classification system. However, no edit validation is currently performed against this field.

code_end_date
The code_end_date is an indicator value, representing the date on which the clinical code ceases to be valid. This field has been present and populated since the introduction of the ICD-10 classification system. However, no edit validation is currently performed against this field.

eligible_cancer_status
An internal-use value only, identifying records that are relevant to the Cancer Registry. Possible values are ‘A’ = Always registrable, ‘S’ = Seldom registrable, ‘N’ = Never registrable and null.

New Zealand edit warning messages

All messages issued by this editing process are warnings, not fatal errors. This means that for an event with a message function code of ‘A1’ these warnings will cause the event to be rejected. The information on the event record may or may not be changed on review by the sending facility. Records that have not been changed and are deemed to be correct by the facility may be re-submitted to the NMDS with the message function code ‘A2’. This will cause the warning messages to be suppressed and the event will be loaded to the NMDS.

Back to top