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Table 1 Definitions of key terms in the computer algorithms. Variables are in italics

From: Classification of positive blood cultures: computer algorithms versus physicians' assessment - development of tools for surveillance of bloodstream infection prognosis using population-based laboratory databases

Term

Definition

Positive blood culture

One observation (row) in the database

Best-estimate-date

Date of draw of blood culture. If date of draw of blood culture is missing: date of receipt of blood culture (never missing)

The patient’s first computer episode

All positive blood cultures on the patient’s earliest best-estimate-date and the day after the earliest best-estimate-date

The patient’s subsequent computer episodes after the first computer episode

First available date after the first computer episode and the day after (second computer episode), first available date after the second computer episode and the day after (third computer episode), etc.

Contamination computer episode

Only common skin commensals (coagulase-negative staphylococci, Propionibacterium spp., Bacillus spp., Micrococcus spp., or Corynebacterium spp.) were detected on only the earliest best-estimate-date of the computer episode within a 5-day period and no pathogens were detected in the computer episode

Bloodstream infection computer episode

A computer episode that is not a contamination computer episode

Monomicrobial bloodstream infection computer episode

Only 1 type of microorganism isolated within the bloodstream infection computer episode

Polymicrobial bloodstream infection computer episode

≥ 2 types of microorganism isolated within the bloodstream infection computer episode

Inpatient contact

A contact recorded in the Danish National Patient Registry (cf. text) in which the patient is hospitalized

Outpatient contact

An ambulatory or emergency room contact in the Danish National Patient Registry (cf. text)

indate

Earliest date of contact, as recorded in the Danish National Patient Registry (cf. text). For an inpatient contact, the date of admission, either from the home or from another hospital ward

outdate

Latest date of contact, as recorded in the Danish National Patient Registry (cf. text). For an inpatient contact, the date of discharge, either to the home or to another hospital ward

time_in

Best-estimate-date minus indate (computed for all combinations of best-estimate-date and indate for each patient, time_in < −2 days omitted)

time_out

Best-estimate-date minus outdate (computed for all combinations of best-estimate-date and outdate for each patient, time_out > 30 days omitted)

Hospital-onset bloodstream infection computer episode

For patients admitted from home to the ward in which the blood culture was retrieved: Bloodstream infection computer episode where the lowest time_in among inpatient contacts is ≥ 2 days

 

Or, for patients admitted from another ward to the ward in which the blood culture was retrieved:

 

 (Bloodstream infection computer episode where the lowest time_in among inpatient contacts is 0 days or 1 day) and (≥ 1 inpatient contacts within the computer episode has time_out = 0 days combined with either time_out minus time_in ≥ 2 days [if time_in = 0 days] or with time_out minus time_in ≥ 1 day [if time_in = 1 day])

 

 or

 

 (Bloodstream infection computer episode where the lowest time_in among inpatient contacts is 0 days or 1 day) and (≥ 1 inpatient contact within the computer episode has time_in > 1 day and time_out < 0 days)

Community-onset bloodstream infection computer episode

Bloodstream infection computer episode where its lowest time_in among inpatient contacts is 0 days or 1 day and the computer episode is not hospital-onset

Healthcare-associated computer episode

A community-onset computer episode with (time_in ≤ 30 days and time_out > 0 days) or (time_in > 30 days and 30 days ≥ time_out > 0 days). time_in and time_out are computed for both inpatient and outpatient contacts