The d_labitems table

Table source: Hospital database.

Table purpose: Definition table for all laboratory measurements.

Number of rows: 753

Links to:

• LABEVENTS on ITEMID

Important considerations

• The ITEMID from MIMIC-III v1.0 does not match the ITEMID from MIMIC-II v2.6. If a mapping between the two is necessary, please contact the guardians of the database.
• Many of the LOINC codes were assigned during a project to standardize the ontology of lab measurements in the MIMIC database. Consequently, the codes were assigned post-hoc, and may not be present for every lab measurement. We welcome improvements to the present codes or assignment of LOINC codes to unmapped data elements from the community.

Table columns

Name	Postgres data type
ROW_ID	INT
ITEMID	INT
LABEL	VARCHAR(100)
FLUID	VARCHAR(100)
CATEGORY	VARCHAR(100)
LOINC_CODE	VARCHAR(100)

Detailed Description

D_LABITEMS contains definitions for all ITEMID associated with lab measurements in the MIMIC database. All data in LABEVENTS link to the D_LABITEMS table. Each unique LABEL in the hospital database was assigned an ITEMID in this table, and the use of this ITEMID facilitates efficient storage and querying of the data. Note that lab items are kept separate while most definitions are contained in the D_ITEMS table, and there were good reasons to keep the lab items separate.

As the laboratory data is acquired from the hospital database, the data is consistent across all years in the database. Consequently, there is usually only one ITEMID associated with each concept in the database. Furthermore, the data contains information collected in departments outside the ICU. This includes both wards within the hospital and clinics outside the hospital. Most concepts in this table have been mapped to LOINC codes, an openly available ontology which provides a rich amount of information about the laboratory measurement including reference ranges, common units of measurement and other further detail regarding the measurement.

ITEMID

As a candidate key in the table, ITEMID is unique to each row.

LABEL

The LABEL column describes the concept which is represented by the ITEMID.

FLUID

FLUID describes the substance on which the measurement was made. For example, chemistry measurements are frequently performed on blood, which is listed in this column as ‘BLOOD’. Many of these measurements are also acquirable on other fluids, such as urine, and this column differentiates these distinct concepts.

CATEGORY

CATEGORY provides higher level information as to the type of measurement. For example, a category of ‘ABG’ indicates that the measurement is an arterial blood gas.

LOINC_CODE

LOINC_CODE contains the LOINC code associated with the given ITEMID. LOINC is an ontology which originally specified laboratory measurements but has since expanded to cover a wide range of clinically relevant concepts. LOINC openly provide a table which contains a large amount of detail about each LOINC code. This table is freely available online or can be provided by the guardians of the database.