Parameters:
(1) Imrie (Glasgow) prognostic score, on admission
(2) C-reactive protein (CRP) on day 3 after admission, using radial imunodiffusion with a normal range < 0.01 g/L (see Figure 1, page 230)
(3) white blood cell count on day 7 after admission
|
Parameter
|
Finding
|
Points
|
|
Imrie prognostic score on admission
|
0 – 2
|
0
|
|
|
3 - 9
|
1
|
|
CRP on day 3
|
<= 0.15 g/L
|
0
|
|
|
> 0.15 g/L
|
1
|
|
WBC count on day 7
|
<= 15 * 10^9/L (<= 15,000 per µL)
|
0
|
|
|
> 15 * 10^9/L (> 15,000 per µL)
|
1
|
number of risk factors present =
= SUM(points for the 3 parameters)
|
Number of Risk Factors
|
Sensitivity for Severe Disease
|
Specificity for Severe Disease
|
|
1
|
95%
|
52%
|
|
2
|
65%
|
83%
|
|
3
|
35%
|
98%
|
On page 231, the authors give the following equations for probability of severe outcome:
probability of severe outcome =
= EXP(X) / (1 + EXP(X))
X for day 1 =
= (0.62827 * (initial Imrie score)) + (0.07055 * (initial WBC count)) – 4.2396
X for day 3 =
= (0.82702 * (on day 3 Imrie score)) + (7.3241 * (CRP on day 3)) – 4.8940
X for day 7 =
= (0.65979 * (on day 7 Imrie score)) + (0.15617 * (WBC count on day 7)) – 4.9089
where:
• I assume that WBC count used is the (value) * 10^9.
Limitations:
• The cutoff point for CRP will probably need to be adjusted for different analytic methods.
