# Table 1 Parameters used to calculate cost impact and cost-effectiveness

Parameter Description Unit Value Source Used in equation
Cost t Full cost per PCR test 300 Additional file 1 1, 4, 5,
DG Days gainable on adequate treatment when utilizing PCR+ information day 2.78 = 80.5/29 [17]a 2,3,4
$D u P C R + I A$ Mean total duration of inadequate treatment (as observed in PCR+ episodes with 0.5 ≤Du IA ≤ 7.5) day 3.28 = 0.5 + DG [17]a 2, 5,
$F L O S I A$ Factor which translates days on earlier adequate treatment into outcome in terms of mean days reduced length of stay (deltaLOS = LOS Inad - LOS Ad ) - 1.15 = 3.763 day/3.276 day $= d e l t a L O S D u P C R + I A$ calculated from [3, 4, 17] 3, 4
$I n P C R + I A$ Incidence of inadequate treatment in the PCR+ group - 0.397 = 29/73 Figure 1 4, 5
LY gained Mean # years survival of survivors of ICU sepsis, age cohort >60 c yr 5.43 b = 12.3 * 488/1105 [26] 6
$M P C R + I A$ Mortality rate of inadequately treated PCR+ patients - 0.414 = 12/29 Figure 1 5
RR Relative risk of non-survival (@ inadequate/adequate treatment) - 2.315 [3, 4, 17] pooled 5
Sh PCR+ Share of episodes with at least 1 PCR+ microorganism - 0.330 = 73/221 Table 2 4, 5
TAT PCR Time between PCR sampling and result reported (hours) hr 12 [17] 2
Utility health.state Health state utility after ICU sepsis QALY/yr 0.68 [26] 6
1. a Not identical with time to positive blood culture, but linked to it in about 50% of contributing data
2. b LYgained (of survivors age >60, according to data from [26]); = LYgained (all included sepsis survivors)* ICER(all)/ICER(age >60) = 12.3 yr * 48,800 \$/110,500 \$ = 5.43 yr.
3. c We use the data for those aged >60 because the mean age in our subgroup with potential survival benefit (Table 3) is 69.1 yr.
4. €, Euro (European currency unit); QALY, quality-adjusted life year.