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Multiple measurements on one measurement_id

Implementers
#1

Hi there,

I wanted to be sure about the convention of wat serves as primary key in the Measurement table. I am going to implement the CDM for databases in which many measurements are executed repititively.

Example:
pO2 is measured for patient x on jan 13
pO2 is measured for patient x on feb 15

In OHDSI’s description about the measurement table is stated that the measurement_id is a unique identifier but this will be undone when a measurement is executed twice. If measurement_date is part of the primary key (together with - at least - measurement_id and person_id) there is no problem. If I cannot store multiple measurements of the same measurement_id on the same patient in this way, please elaborate on a solution.

Thank you in advance!

#2

in i2b2 for example, I am aware of an “instance number”. I have not found anything like this in the OHDSI OMOP conventions yet.

#3

@borditewig:

It’s very simple: You can record Measurements as often as you want, the same day, hour or minute. If that indeed happened and there are no duplicates, but you as the data owner would know that. The measurement_id is a simple counter. Just start from 1 or 7 or 1500 and count them up, one unique measurement_id value per record.

1 Like
#4

Thank you for the quick response! I don’t know how I kept on not seeing there was measurement_concept_id AND measurement_id.

All clear now, thank you again.

t