Table 3. Sensitivity analyses of laboratory-specific parameters to compare time and cost estimates of breast cancer biomarker analysis using immunohistochemistry and Xpert® STRAT4 assay, Rwanda, 2021.
| Parameter | Immunohistochemistry |
Xpert® STRAT4 |
Absolute saving (relative saving, %) achieved by using STRAT4 |
|||||
|---|---|---|---|---|---|---|---|---|
| Personnel time, minutes | Cost, US$ | Personnel time, minutes | Cost, US$ | Personnel time, minutes | Cost, US$ | |||
| Cost estimate per patienta | 33 | 67.33 | 13 | 60.00 | 20 (60.6) | 7.33 (10.9) | ||
| Immunohistochemistry batches (primary: 40 slides) | ||||||||
| 72 slides | 31 | 66.80 | 13 | 60.00 | 18 (58.1) | 6.80 (10.2) | ||
| 20 slides | 38 | 68.53 | 13 | 60.00 | 25 (65.8) | 8.53 (12.4) | ||
| Antibody utilization efficiency (primary: 70%)b | ||||||||
| 90% of antibody vial used | 33 | 60.07 | 13 | 60.00 | 20 (60.6) | 0.07 (0.1) | ||
| 80% of antibody vial used | 33 | 63.27 | 13 | 60.00 | 20 (60.6) | 3.27 (5.2) | ||
| 60% of antibody vial used | 33 | 72.85 | 13 | 60.00 | 20 (60.6) | 12.85 (17.6) | ||
| No. receptors analysed (primary: three) | ||||||||
| One (estrogen receptor) | 11 | 21.77 | 13 | 60.00 | −2 (−18.2) | −38.23 (−175.6) | ||
| Two (estrogen and progesterone receptors) | 22 | 46.24 | 13 | 60.00 | 9 (40.9) | −13.76 (−29.8) | ||
| Four (estrogen and progesterone receptors, human epidermal growth factor receptor-2, Ki67) | 44 | 82.78 | 13 | 60.00 | 31 (70.5) | 22.78 (27.5) | ||
| STRAT4 batching (primary: 4-module GeneXpert® system)c | ||||||||
| 16-module GeneXpert® system | 33 | 67.33 | 13 | 59.33 | 20 (60.6) | 8.00 (11.9) | ||
| 2-module GeneXpert® system | 33 | 67.33 | 13 | 60.98 | 20 (60.6) | 6.35 (9.4) | ||
| Xpert® cartridge price (primary: US$ 50.00)d | ||||||||
| US$ 40.00 | 33 | 67.33 | 13 | 49.00 | 20 (60.6) | 18.33 (27.2) | ||
| US$ 30.00 | 33 | 67.33 | 13 | 38.00 | 20 (60.6) | 29.33 (43.6) | ||
| US$ 20.00 | 33 | 67.33 | 13 | 27.00 | 20 (60.6) | 40.33 (59.9) | ||
| US$ 14.90 (price of Xpert® SARS-CoV-2 cartridge kit) | 33 | 67.33 | 13 | 21.39 | 20 (60.6) | 45.94 (68.2) | ||
| US$ 9.98 (price of Xpert® MTB/RIF Ultra cartridge kit) | 33 | 67.33 | 13 | 15.98 | 20 (60.6) | 51.35 (76.3) | ||
MTB/RIF: Mycobacterium tuberculosis/rifampin resistance; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; US$: United States dollars.
a Estimates are taken from Table 2.
b The antibody utilization efficiency was based on the estrogen receptor antibody utilization efficiency of the laboratory.
c 2-, 4- and 16-module batching for STRAT4 corresponds to 14-, 28- and 112-sample batching for preparation, respectively, assuming that the GeneXpert® system can be run seven times in 1 day (each run takes 70 min).
d The price of the 2-, 4- and 16-module Xpert® machines was US$ 12 030, 17 500 and 64 350, respectively. The price of Xpert® STRAT4 was assumed to be similar to that of the Xpert® BCR-ABL Ultra cartridge, that is, US$ 50 per cartridge kit.
Note: Cost in US$ converted from Rwandan francs in 2021. Time and cost data rounded to nearest minute and cent, respectively, for inclusion in table.