Table 3.
Procedure volume and estimated normative cost per patient diagnosed and treated under Cambodia’s TB diagnostic algorithms for PLHIV and people with presumptive MDR TB (costs in 2017 U.S. dollars)
| Procedure | PLHIV Pre-Xpert Algorithm (no drug resistance) |
PLHIV Post-Xpert Algorithm (no drug resistance) |
MDR TB Pre-Xpert Algorithm | MDR TB Post-Xpert Algorithm | |
|---|---|---|---|---|---|
| Clinical diagnostic assessment | Procedure Frequency | 1 time | |||
| Unit Cost | US$1.22-US$1.84 | ||||
| Chest x-ray, automatic development | Procedure Frequency | 1 time | |||
| Unit Cost | US$2.02-US$2.14 | ||||
| Smear Microscopy – FM | Procedure Frequency | 3 tests | |||
| Unit Cost | US$1.56-US$1.93 | ||||
| Xpert® MTB/RIF | Procedure Frequency | 1 test | 1 test | ||
| Unit Cost | US$33.88-US$37.11 | US$33.88-US$37.11 | |||
| Liquid Culture – MGIT | Procedure Frequency | 2 tests | 2 tests | ||
| Unit Cost | US$11.63-US$22.83 | US$11.63-US$22.83 | |||
| Follow-on work up for positive MGIT results and MTB identification | Procedure Frequency | 2 tests | 2 tests | ||
| Unit Cost | US$11.50-US$14.72 | US$11.50-US$14.72 | |||
| Drug Susceptibility Testing (DST) | Procedure Frequency | 2 tests | 2 tests | ||
| Unit Cost | US$44.26 | US$44.26 | |||
| DIAGNOSTIC TEST COSTS per TB+ patient (assuming perfect accuracy)* | US$8.56-US$9.14 | US$33.88-US$37.03 | US$134.77-US$163.62 | US$168.65-US$200.65 | |
| Community Directly Observed Therapy Short Course (C-DOTS) | Procedure Frequency | 6 months | 6 months | ||
| Unit Cost (per month) | US$8.60-US$11.21 | US$8.60-US$11.21 | |||
| First Line Drugs (6 months) | Procedure Frequency | 6 months | 6 months | ||
| Unit Cost (per month) | US$4.35 | US$4.35 | |||
| Treatment Monitoring Smear Microscopy – ZN | Procedure Frequency | 3 tests | 3 tests | ||
| Unit Cost | US$1.26 | US$1.26 | |||
| TREATMENT COSTS per TB+ patient (assuming perfect test accuracy) | US$81.42-US$97.12 | US$81.42-US$97.12 | |||
| Scenario without perfect test accuracy | |||||
| False positive rate (1-specificity)1 | 0% | 1% | |||
| False negative rate (1-sensitivity)1 | 27% | 12% | |||
| Necessary treatment costs per patient due to true positives | US$59.43-US$70.90 | US$71.65-US$85.47 | |||
| Unnecessary treatment costs per patient due to false positives | US$0.00 | US$0.81-US$0.97 | |||
| Treatment cost increase per patient under post-Xpert algorithm compared to pre-Xpert algorithm (without perfect test accuracy, using assumed sensitivity and specificity) | US$13.03-US$15.54 | ||||
| Diagnostic cost increase per patient under post-Xpert algorithm compared to pre-Xpert algorithm (without perfect test accuracy, using assumed sensitivity and specificity) | US$25.32-US$27.89 | ||||
| Total increase in diagnosis and treatment costs per patient under post-Xpert algorithm compared to pre-Xpert algorithm (without perfect test accuracy, using assumed sensitivity and specificity) | US$40.86-US$40.92 | ||||