Sample size and power considerations
We estimated the required sample based on the primary outcome of VL suppression at 48 weeks. Under usual care, viral suppression rate was about 60%. We hypothesized that the clinic-based VL testing SAMBA intervention would improve care to achieve viral suppression to 90% after 12 months. We estimated that, with a total of 356 CALWH on ART, we could detect at least a 15% increase in virologic suppression with 90% power at 0.05 significance level, assuming a 10% lost to follow up.