I’m implementing a ETL for ‘drug_exposure’ table, and am struggling to understand how to fill the quantity field for liquids.

For instance, drug_concept_id = 19079524 (sodium chloride 9 MG/ML Injectable Solution). I would expect ‘drug_strength’ to have the following values

|numerator_value|9.0|

|numerator_unit_concept_id|8576 (mg)|

|denominator_value|1.0|

|denominator_unit_concept_id|8587 (mL)|

However, the actual value for ‘denominator_value’ is NULL, what makes no sense to me.

Other example, for concept_id = 19036828 (10 ML calcium chloride 100 MG/ML Injection), we have

|numerator_value|1000.0|

|numerator_unit_concept_id|8576|

|denominator_value|10.0|

|denominator_unit_concept_id|8587|

This time the proportion is right (1000/10) however, the title specifies 100mg/10mL, so why are the ‘numerator_value’ and ‘denominator_value’ 10x bigger?

Should I assume that, when ‘denominator_value’ is NULL and ‘denominator_unit_concept_id’ is not zero, then the actual denominator value is 1?

Thanks