Table 2 Calculation of expected costs in decision model (using the example of strategy “targeted PCR screening with pre-emptive isolation measures”)
Combinations of true and tested MRSA status of screened patients | Costs per patient*: | Number of patients*: |
|---|---|---|
MRSA positive | C PCR + C culpos + C preiso * (T PCR + T cul ) + C MRSA * (Ø LOS MRSA - T PCR -T cul ) + C c *Pat c + Ø LOS MRSA * RT iso * C MRSA * Ø LOS MRSA | Pat risk * P risk * Sen PCR * Sen cul |
PCR (+) and culture (+) → true positive | ||
MRSA negative | C PCR + C culpos + C preiso * (T PCR + T cul ) + C MRSA * (Ø LOS MRSA - T PCR -T cul ) + C c *Pat c | Pat risk * (1 - P risk ) * (1 - SP PCR ) * (1 - SP cul ) |
but PCR (+) and culture (+) → false positive | ||
MRSA positive | C PCR + C culneg + C preiso * (T PCR + T cul ) + [(Ø LOS MRSA - T PCR -T cul ) * RT noiso + (T PCR + T cul ) * RT iso ] * C MRSA * Ø LOS MRSA | Pat risk * P risk * Sen PCR * (1 - Sen cul ) |
PCR (+), no confirmation because culture (-) → false negative | ||
MRSA negative | C PCR + C culneg + C preiso * (T PCR + T cul ) | Pat risk * (1 - P risk ) * (1 - SP PCR ) * SP cul |
PCR (+), no confirmation because culture (-) → false positive | ||
MRSA positive | C PCR + C preiso * T PCR + [(Ø LOS MRSA - T PCR ) * RT noiso * + T PCR * RT iso ] * C MRSA * Ø LOS MRSA | Pat risk * P risk * (1 - Sen PCR ) |
but PCR (-), no culture test conducted → false negative | ||
MRSA negative | C PCR + C preiso * T PCR | Pat risk * (1 - P risk ) * SP PCR |
PCR (-), no culture rest conducted → true negative | ||
No high-risk patients (screening is not indicate) | Cost due to transmission (of MRSA-Patients, who were not screened) | Number of patients |
MRSA positive | Ø LOS MRSA * RT noiso * C MRSA * Ø LOS MRSA | Pat n.i. * P n.i. |
MRSA negative | no costs | Pat n.i. * (1-P n.i. ) |