The following costs and rates, provided with references, are used in the calculations.
Treatment costs used in calculations
| Screening cost1 |
| IGRA* |
$ 87.79 |
| TST** |
$ 27.95 |
| Treatment costs for a 9-month course of isoniazid (INH) |
| Patient self-administered treatment (SA)2 |
$ 258.72 |
| Directly-observed preventive treatment (DOPT)3 |
$ 2,007.01 |
| Cost to rule out a diagnosis of TB6 |
| Chest X-Ray |
$ 21.00 |
| Clinic visit |
$ 73.00 |
| Clinic follow-up rate for diagnosis |
0.90 |
| Cost to treat one case of TB with a 6-month course of INH treatment4 |
$ 13,909.53 |
| Cost of short course LTBI treatment regimens5 |
| 3-month course of directly observed weekly Isoniazid and Rifapentine (3HP) |
$ 548.85 |
| 4-month daily course of self-administered Rifampin (4R) |
$ 231.42 |
Rates used in calculations
| |
Diagnostic Method |
| |
TST |
IGRA |
| Read rate1,2 |
0.88 |
1 |
| Test specificity5, 6, 7, 8, 9, 10, 11, 12, 13 |
0.85 |
0.99 |
| Test sensitivity among patients who are not immunocompromised5, 6, 7, 8, 9, 10, 16 |
0.89 |
0.83 |
| Test sensitivity among immunocompromised patients8 |
N/A |
0.90 |
| Overall positive predictive value (PPV)15 overall |
|
0.06 |
| False positive |
0.15 |
0.01 |
| True negative (negative predictive value) |
0.995 |
0.995 |
| Hepatotoxicity3 |
0.027 |
| Treatment stopped due to adverse reaction |
0.037 |
| Average risk reduction of developing TB after having taken treatment |
0.69 |
| TB risk reduction from partially completed treatment, 1-83 days |
0.21 |
| TB risk reduction from partially completed treatment, 3 to 5 months4, 14 |
0.30 |
| TB risk reduction from partially completed treatment, 6 to 8 months4, 14 |
0.60 |
| TB risk reduction from partially completed treatment, 9 months14 |
0.90 |
| Partial treatment completion rate17, 18 |
0.375 |
| Partial treatment completion rate, 1 to 83 days |
0.16 |
| Partial treatment completion rate, 84 to 167 days |
0.15 |