In patients with ascites the diagnosis of bacterial infection needs to be made rapidly so that appropriate antibiotic therapy can be started as soon as possible.
Characteristics of Ascitic Fluid and Arterial Blood
|
Criteria |
Infected |
Noninfected |
Malignant |
|
ascites fluid pH |
7.20 +/- 0.19 |
7.44 +/- 0.06 |
7.39 +/- 0.09 |
|
(arterial blood pH) - (ascites pH) |
0.23 +/- 0.17 |
0.01 +/- 0.06 |
0.08 +/- 0.10 |
|
(arterial blood lactate) - (ascites lactate) |
-46 +/- 31 mg/dL |
-6 +/- 10 mg/dL |
-27 +/- 35 mg/dL |
|
ascitic fluid PMNs |
18,199 +/- 19,650 per µL |
119 +/- 311 |
121 +/- 267 |
|
ascitic fluid lactate |
80 +/- 51 mg/dL |
19 +/- 12 mg/dL |
38+/- 36 mg/dL |
Diagnosis of Infected Ascites Fluid Using Single Criteria
|
Criteria |
Cutoff |
Sensitivity |
Specificity |
|
ascites fluid pH |
<= 7.34 |
89% |
100% |
|
(arterial blood pH) - (ascites pH) |
>= 0.10 |
89% |
97% |
|
(arterial blood lactate) - (ascites lactate) |
<= -20 mg/dL |
89% |
94% |
|
ascitic fluid PMNs |
> 500/µL |
89% |
92% |
|
ascitic fluid lactate |
>= 39 mg/dL |
89% |
92% |
Diagnosis of Infected Ascites Fluid Using Dual Criteria
|
Criteria 1 |
Criteria 2 |
Sensitivity |
Specificity |
|
ascites fluid pH <= 7.34 |
ascitic fluid PMNs > 500/µL |
89% |
100% |
|
(arterial blood pH) - (ascites pH) >= 0.10 |
ascitic fluid PMNs > 500/µL |
89% |
100% |
|
ascitic fluid lactate >= 39 mg/dL |
ascitic fluid PMNs > 500/µL |
89% |
100% |
|
(arterial blood lactate - ascites lactate) <= -20 |
ascitic fluid PMNs > 500/µL |
89% |
100% |
Recommended tests for diagnosis of ascitic fluid infection:
(1) ascitic fluid pH <= 7.34
(2) ((arterial blood pH) - (ascitic fluid pH) >= 0.10) + (ascitic fluid PMNs > 500/µL)
Specialty: Gastroenterology
ICD-10: ,
