These are the PRIMED harmonization instructions for white blood cell count (WBC).
To ascertain a single white blood cell count value per individual, adhere to the instructions as follows:
1. Extract trait measurements using measurement codes and calculations
2. Convert measurement units to expected units, if necessary
3. Apply individual exclusion criteria
4. Apply measurement exclusion criteria, other than statistical outliers
5. Remove statistical outliers
6. Compute a single value per individual for inclusion in analysis
7. Calculate counts of flagged individuals
Codes used to ascertain these WBC values are noted in a separate file, along with exclusion codes for individuals with conditions/diagnoses at any time point. Please convert all measurements to 1-^9/L to adhere to expected units in this algorithm.
Additional exclusions include: Age at measurement <18 years, Exclude measurements taken at Inpatient or Emergency Department visits. Alternatively, keep only measurements taken at Outpatient visits. Take whichever approach is most appropriate for your EHR. Exclude measurements occurring within 90 days of any sepsis diagnosis codes (up to 90 days before or 90 days after)
Exclude measurements with value 0
After these exclusions, remove statistical outliers outside of +/- 6 SD from the overall mean WBC count
Compute a single value per individual by calculating the median WBC for each individual, calculate median age for each individual from the same timepoint of the WBC chosen. There is no minimum number of visits or measurements.
