Here is the design of a clinical trial:

Official Title: MyTPill: A Novel Strategy to Monitor Antiretroviral Adherence Among HIV+ Prescription Opioid Users

Included conditions:
- HIV-positive Individuals

Study Armgroups:
- {'label': 'MyTPill', 'description': 'Participants receive digital pills for three months, have a 2-week washout, then switch to Wisepill.', 'interventionNames': ['Device: MyTPill, a digital pill']}

Interventions:
- {'type': 'DEVICE', 'name': 'MyTPill, a digital pill', 'description': 'MyTPill is a digital pill containing an approved medication', 'armGroupLabels': ['MyTPill'], 'otherNames': ['Wisepill, a digital pillbox']}

Primary Outcomes:
- {'measure': 'Dried blood spots', 'description': 'Measurement of dried blood spots for TDF/FTC concentrations', 'timeFrame': 'six months'}
- {'measure': 'Adherence per two different electronic adherence measures', 'description': 'Secondary outcomes are the identification of multi-level factors that are prevalent in the target population most closely linked to ART non-adherence and EAM non-adherence.', 'timeFrame': 'Six months'}

Please estimate the sample size based on the assumption: 
The study assumes a significance level that allows for 90% power to detect the absolute difference. An estimated 20% attrition rate is considered, and the comparison is based on two-sample binomial proportion using Fisher's exact test.
Sample size
        Our sample size of 80 participants (40 per study arm Ã 2 study arms; estimated 20% attrition) is based on satisfying the primary aim of the study: the comparison of ART adherence efficacy of the MyTPill versus the Wisepill system. The benefit of the cross-over design permits comparison of participants across study arms (MyTPill first 3 months vs Wisepill first 3 months and MyTPill second 3 months vs Wisepill second 3 months) and within study arms (MyTPill vs Wisepill for the same participant). Comparisons within study arms permit a reduction in variance and enables detection of statistical difference with smaller effect sizes, as compared with the across study arms comparisons.
        The accuracy of the MyTPill and Wisepill measurements will be determined by examining the concordance between these measurements and the âgold standardâ DBS. As such, concordance can be considered a continuous value with a range from 0 to 100. Recent adherence is assessed by the presence of FTC-TP in DBS samples in a binomial fashion: adherent or non-adherent within the prior 48 hours. In an analogous fashion, MyTPill and Wisepill indicate whether or not ARTs were ingested (MyTPill) or the pill bottle opened (Wisepill) at least once in the prior 48 hours. Two DBS will be obtained per participant per month (12 total; 6 DBSs during Wisepill and 6 DBSs during MyTPill) for a total of 960 DBSs. If 20% are not collected or are not readable for any reason, there would be 768 samples. For this investigation, which is the first of its kind, there is no clinical standard to base the effect size, and no prior pilot studies to base the estimate. An effect size of 10%â15% seems to be a reasonable gestalt estimate in comparing two behavioural interventions for adherence. Using an estimate absolute difference of 10% reflects a hypothesis that one intervention has 10% greater absolute adherence than the other intervention. The sample size is based on the number of blood samples that are concordant and as such a sample size of 80 participants providing at least 768 dried blood samples permits approximately 90% power in detecting that absolute difference. The study would have greater power for a larger effect size of 15%, if detected. In this case, the comparison is two-sample binomial proportion. Using Fisherâs exact test to examine differences in measures of concordance between the MyTPill and Wisepill, we can detect with high power (>0.9) an effect size of an absolute difference of at least 10%â15% of greater concordance with the DBS gold standard.