This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Topical Antimicrobial Effectiveness Testing (NCT01314703), a na phase 4 study. The primary outcome is Antimicrobial Efficacy Will be Measured by the Change (+/-) in Bacterial Count on the Skin 10 Minutes After a Single Application of Test Material Relative to the Baseline Bacterial Count..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01314703 |
| Phase | Phase 4 |
| Condition | Antimicrobial Effectiveness |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | Single |
| Enrollment | 27 |
| Arms in the primary outcome | n/a |
| Lead sponsor | C. R. Bard |
| Results posted | Yes |
2. Clinical Question
The study asked whether bacterial recovery from the skin changed after a single application of ChloraPrep One-Step. Its primary outcome was the change from baseline bacterial count to the count recovered 10 minutes after application, measured separately at abdominal and groin treatment sites.
Population
The registry record describes 27 subjects treated at abdominal and groin sites. For analysis, 26 abdominal sites and 25 groin sites met the qualifying baseline bacterial-count criterion. The record does not further characterize the subjects.
Intervention
The primary objective names ChloraPrep One-Step, and the outcome description specifies a single application of test material. The listed interventions are ChloraPrep One-Step and 70% isopropyl alcohol; the record does not describe the use or role of 70% isopropyl alcohol in the reported outcome.
Comparator
This is a single-group study, not a randomized comparison. The registry record does not report a concurrent control group or establish a like-for-like comparison between ChloraPrep One-Step and 70% isopropyl alcohol.
Primary question
What was the mean change in bacterial count on the skin 10 minutes after a single application, relative to baseline? The endpoint is expressed in log 10 colony forming units. Numerical mean changes and confidence intervals are not reported in the registry record.
3. Trial Design
The registry identifies NCT01314703 as a completed phase 4 study titled “Topical Antimicrobial Effectiveness Testing,” with the official title “Test for Preoperative Skin Preparations.” The sponsor was C. R. Bard. The listed study start was 2011-03 and primary completion was 2011-04. Enrollment was 27.
The design is classified as single-group, with allocation listed as NA and single masking. These classifications do not describe a randomized, parallel-group comparison. The record does not report further details about who was masked or how masking was implemented. It also does not report a protocol or statistical analysis plan.
The primary objective was to measure the antimicrobial effectiveness of ChloraPrep One-Step. The outcome description concerns bacterial recovery at baseline and 10 minutes after a single application. Subjects were treated at abdominal and groin sites. The analysis population depended on whether each site met the qualifying baseline bacterial-count criterion: 26 of 27 abdominal sites and 25 groin sites qualified.
Although 70% isopropyl alcohol is listed as an intervention, the record does not describe a randomized or concurrent comparison involving it. The listed intervention alone is not evidence that the study compared the two materials. The study record identifies one outcome measure and four analyses, but does not give enough detail to identify the specific analysis procedures or how the four analyses relate to one another.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: 35 subjects entered pre-screening phase.2 subjects withdrew consent prior to the Screen Visit.33 subjects completed screen baseline.3 subjects did not meet screen baseline criteria.30 subjects qualified for treatment.3 subjects were discontinued prior to treatment because the required number of treatment sites were met. 27 subjects were treated.
Overall Study
| Stage | ChloraPrep and 70% Isopropyl Alcohol |
|---|---|
| STARTED | 35 |
| Signed Informed Consent | 35 |
| Completed Screen Visit | 33 |
| Completed Treatment Visit | 27 |
| Completed Study | 27 |
| Excluded Prior to Screening Baseline | 2 |
| Non Qualified Bacterial Screening Counts | 3 |
| Discontinued When Enrollment Completed | 3 |
| COMPLETED | 27 |
| NOT COMPLETED | 8 |
Reasons for not completing this period:
| Reason | ChloraPrep and 70% Isopropyl Alcohol |
|---|---|
| screen failure and closed enrollment | 8 |
Analysis population for the primary outcome, as defined in the registry: 27 subjects were treated with ChloraPrep on the abdomen and groin treatment sites. 26 of the 27 abdomen sites met the qualifying bacterial baseline count and were included in the analysis. 25 of the groin sites met the qualifying bacterial baseline count and were included in the analysis.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Group 1 |
|---|---|---|
| Participants analysed | 27 | |
| Age, Continuous | years | 35 (SD 12.7) |
| Age, Continuous | years | 35 (SD 12.7) |
| Sex: Female, Male: Female | Participants | 9 |
| Sex: Female, Male: Male | Participants | 18 |
| Region of Enrollment: United States | participants | 27 |
6. Primary Endpoint
The registry lists the primary outcome as Antimicrobial Efficacy Will be Measured by the Change (+/-) in Bacterial Count on the Skin 10 Minutes After a Single Application of Test Material Relative to the Baseline Bacterial Count., measured over 10 minutes after single application of test material.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | log 10 colony forming units |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is a change in bacterial count on the skin, measured 10 minutes after a single application of test material relative to the baseline count. It is expressed in log 10 colony forming units, and the endpoint is described as a mean. The record defines the change by subtracting the 10-minute post-application bacterial recovery from baseline bacterial recovery.
With that subtraction order, a positive change would correspond to lower recovery after application than at baseline; a negative change would correspond to higher recovery after application. This describes the direction implied by the endpoint definition, not the observed result. The numerical change is not reported in the registry record.
A bacterial-count change is used to quantify the short-term change in recoverable bacteria after application. Reporting the measure on a log scale expresses differences in bacterial counts on a transformed scale, rather than as a raw count. A mean provides a summary across the qualifying sites, while a confidence interval is intended to convey the precision of that estimated mean. The registry record names a 95% confidence interval but does not give its endpoints.
The outcome was assessed for abdominal and groin sites, with separate qualifying-site counts described for each. Those counts define which sites contributed to analysis; they do not themselves indicate the size or direction of the antibacterial change.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the question, measurement time and analysis populations, but does not report the numerical mean changes or their 95% confidence intervals. Consequently, the posted information in this record does not establish the observed magnitude or precision of the change in bacterial recovery at either site. The direction implied by the endpoint definition can be interpreted, but an observed direction cannot be stated without the actual estimates.
The endpoint is defined as baseline bacterial recovery minus recovery 10 minutes after application. Under that definition, a positive estimate would indicate lower recovery at the post-application measurement than at baseline, while a negative estimate would indicate higher recovery. These are explanations of the scale and sign convention, not claims about the study’s results. The record does not give values that would establish either pattern.
The analysis included 26 abdominal sites and 25 groin sites that met the qualifying baseline-count criterion. The overall enrollment was 27. The number of qualifying sites is relevant to interpreting the precision of each site-specific estimate, but the available record does not provide the estimates or confidence intervals needed to judge that precision. The record also does not explain why some sites did not meet the criterion.
The single-group design is important to interpretation. A baseline measurement can describe change over time within treated sites, but the registry classification does not indicate a randomized control comparison. The record therefore does not support attributing a difference between groups to one material over another. Although 70% isopropyl alcohol is listed among interventions, its role in the reported analysis is not described.
The registry lists one outcome measure and four analyses, but does not report the detailed analysis methods, any adjustment for multiple analyses, or how the four analyses correspond to sites or other comparisons. Without those details and numerical results, the posted registry information is insufficient to evaluate the size, uncertainty, or robustness of the outcome finding. The data described are also limited to the 10-minute assessment; the record does not report longer-term measurements.
9. Statistical Methods Explained
The statistical methods can be understood from the outcome definition and the limited design information in the registry record. The endpoint is continuous: it is a numerical bacterial-count change expressed in log 10 colony forming units. The summary measure is a mean, and the record names a 95% confidence interval as the measure of dispersion. The registry record does not report the numerical means or interval limits, nor does it specify the computational method used to obtain them.
What does a mean change summarize?
In general, a mean summarizes the values of a continuous outcome across the observations included in an analysis. In this study, the outcome is defined as baseline recovery minus recovery at 10 minutes after application. A mean change therefore summarizes the site-level changes within the qualifying analysis population. It does not show how much individual sites varied unless additional distributional information is reported. No such individual-level distribution is described in the registry record.
The qualifying populations are reported separately by site: 26 abdominal sites and 25 groin sites. These are the populations described for analysis, not a report of the mean results. The registry record does not state whether the statistical analyses treated sites from the same subject as independent, accounted for within-subject correlation, or used any other modeling approach. Such details can matter when one subject contributes measurements at multiple sites, but the analysis approach is not reported.
How should a confidence interval be read?
In general, a confidence interval expresses uncertainty around an estimated quantity under the assumptions of the method used to calculate it. A narrower interval indicates greater statistical precision than a wider interval for the same kind of estimate. A 95% confidence interval is the interval level named for this endpoint. It does not mean that 95% of individual site outcomes fall within the interval, and it does not on its own establish the practical importance of an estimate.
The interval endpoints are not reported in the registry record. It is therefore not possible to assess their width, whether they include zero, or how compatible the data are with changes in either direction. Those judgments require the actual estimate and interval, not merely the fact that an interval was specified.
What does the design imply for comparisons?
The study is classified as single-group and allocation is listed as NA. The outcome uses a baseline measurement, so the described endpoint is a within-site change relative to baseline. In general, a before-and-after change can be affected by factors that also change over time; without a concurrent randomized comparator, the change does not by itself separate the material’s effect from other possible influences. The registry record does not describe a randomized comparison. It lists 70% isopropyl alcohol as an intervention, but does not establish that it was used as a comparator in the reported analyses.
The primary endpoint’s subtraction order determines how to read its sign. As a general matter, the stated formula makes a positive value correspond to lower post-application recovery than baseline, and a negative value correspond to higher recovery. That sign convention is not a substitute for the missing numerical result.
What is known about the analysis plan?
The record lists four analyses and one outcome measure. It does not identify the statistical test, model, assumptions, handling of outliers, or whether the analyses were prespecified. It also does not report whether there were interim analyses or a formal statistical analysis plan. These details are not reported in the registry record, so no particular procedure should be inferred.
For general context, the mean and its confidence interval are useful when the scientific question concerns an average change and uncertainty around that average. However, interpretation depends on the distribution and design as well as the summary statistic. If observations are more variable than a method assumes, uncertainty may be understated; if measurements within a subject are correlated, treating them as independent can also misstate precision. Whether either issue affected this study cannot be determined because the analysis details are not reported.
Planning illustrations use a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation, with the detectable effect set to a stated fraction of the observed effect. Those are planning assumptions, not evidence that this single-group study was designed or analyzed using a two-arm comparison. The illustrations are not observed power. The record does not report the trial’s own sample-size justification, and the observed effect needed to interpret such illustrations is not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one outcome measure and four analyses. It does not explain whether the analyses represent different sites, different statistical approaches, or another set of comparisons. The record does not report whether a multiplicity adjustment was planned or used. In general, when several statistical hypotheses are tested, the chance of at least one apparently unusual result can increase if no adjustment is made. Whether that concern applies to these four analyses depends on their structure, which is not described.
The outcome populations are specified by qualifying baseline counts: 26 abdominal sites and 25 groin sites. The record does not describe how observations that failed the qualifying criterion were handled beyond stating that they were not included in the corresponding analysis. It does not report the reasons for nonqualification or describe any other missing-data handling, such as imputation or sensitivity analyses. Those procedures are not reported in the registry record.
The record gives an enrollment of 27 and describes treatment at abdominal and groin sites, but does not provide a full accounting of missing measurements, withdrawals, or exclusions beyond the qualifying-site counts. It also does not identify a broader analysis population or state whether all treated subjects were included in every analysis. Therefore, the analysis populations should be read as the site counts explicitly described, not as evidence about other analysis sets.
In general, missingness can affect interpretation if the sites without qualifying measurements differ systematically from those included. The registry information does not show whether that occurred. It also does not report the statistical analysis plan or interim-analysis procedures, so these aspects cannot be reconstructed from the listed outcome and analysis counts.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Group 1 | 0 | 27 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Group 1 | 0 of 27 |
The safety figures list 27 subjects at risk for serious adverse events and zero subjects affected. The separate other-adverse-event figures also list 27 at risk and zero affected. No serious adverse-event terms are listed. These are the counts recorded in the registry entry; they should be read as reported event counts for this study, not as evidence that risk is absent.
The deaths field is null. A null value is not the same as a reported count of zero, so deaths are not reported in the registry record. The record does not specify the safety observation period or provide further detail about event collection, event severity definitions, or the relationship of any event to treatment. It also does not provide event-level information beyond the listed counts and terms.
With 27 subjects at risk, the recorded zero affected subjects is a description of the registry data, not a precise estimate that an event cannot occur. In general, small studies have limited ability to characterize uncommon events. The listed counts do not establish safety for other populations, longer observation periods, or settings beyond the study record.
12. What the Result Does, and Does Not, Mean
This study is described as an assessment of short-term change in bacterial recovery after a single application of ChloraPrep One-Step. Its primary endpoint is a baseline-to-10-minute change in log 10 colony forming units, and the qualifying analysis populations are identified for abdominal and groin sites. The record also identifies a 95% confidence interval as the endpoint’s dispersion measure.
The numerical outcome estimates and confidence intervals are not reported in the registry record. As a result, the record does not establish how large the mean change was, how precisely it was estimated, or whether the observed change was positive or negative. The endpoint definition explains how those values would be interpreted, but cannot stand in for the values themselves.
The design is single-group rather than a randomized comparison. A change relative to baseline is not the same as a comparison against an untreated group or another preparation. The listing of 70% isopropyl alcohol as an intervention does not establish that the study compared it with ChloraPrep One-Step. The registry record does not describe such a comparison.
The results described are limited to the 10-minute post-application measurement. The record does not report evidence about persistence of the change, other time points, or outcomes beyond the listed bacterial-count measure. Nor does it report details needed to assess the statistical analysis, including methods for the four listed analyses or handling of data beyond the qualifying-site criteria.
Accordingly, the record supports describing the study question, design classification, outcome definition and analysis counts. It does not support a quantitative conclusion about the size or precision of the bacterial-count change, a comparative conclusion between preparations, or a broader claim about clinical outcomes. These boundaries reflect what is and is not reported in the registry record.
13. Why This Trial Matters Statistically
This study illustrates the distinction between a clearly defined endpoint and a fully interpretable result. The registry specifies the bacterial-count change, the subtraction order, the 10-minute measurement time and the unit. These details make the intended outcome understandable. Yet without the mean estimates and confidence intervals, readers cannot assess the observed change or its precision.
It also highlights how design affects the question a result can answer. The study is identified as single-group, with allocation listed as NA. Its endpoint compares post-application recovery with baseline; it does not, on the information reported, provide a randomized comparison between preparations. A within-group change and a between-group treatment contrast are different statistical quantities and support different interpretations.
The site-specific qualifying counts matter because the analyzed observations were not described simply as all 27 enrolled subjects at both sites. The record gives 26 qualifying abdominal sites and 25 qualifying groin sites. Such population definitions are part of the result’s context, and the reason some sites did not qualify is not reported.
Finally, the record lists four analyses but does not explain their relationship or describe multiplicity handling. This makes transparent reporting of the analysis plan important: readers need to know what was tested, how uncertainty was calculated, and how results were selected for reporting. The record’s limitations show why endpoint definitions, analysis populations, numerical estimates and design details must be considered together when interpreting clinical-trial statistics.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main interpretive limitation is that the numerical primary outcome estimates and 95% confidence intervals are not reported in the registry record. The record therefore does not permit evaluation of the observed mean change, its precision, or its direction. The outcome definition and population counts alone are not sufficient to judge the magnitude of the result.
The study is classified as single-group, so the registry record does not describe a randomized comparison. It lists both ChloraPrep One-Step and 70% isopropyl alcohol as interventions, but does not explain the latter’s role in the reported analysis. A comparative effect between those materials cannot be established from the design details given.
The analysis population is described through qualifying baseline bacterial counts: 26 abdominal sites and 25 groin sites. The record does not explain why other sites did not qualify, describe additional missing data, or report sensitivity analyses. It also does not specify whether observations from abdominal and groin sites on the same subject were modeled as related.
Although four analyses are listed, their methods and relationship are not described. Statistical tests, model assumptions, multiplicity procedures and details of the analysis plan are not reported in the registry record. The record likewise does not report interim-analysis procedures or the study’s sample-size justification. The listed planning assumptions are illustrations and do not replace a reported trial-specific justification.
Finally, the primary endpoint addresses bacterial recovery 10 minutes after a single application. The registry record does not report other measurement times or broader clinical outcomes. Safety reporting is limited to the listed counts, with deaths not reported in the registry record. These constraints limit what can be concluded from the record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Topical Antimicrobial Effectiveness Testing — NCT01314703.
- Registry record last updated 2025-12-11; status last verified 2025-11.
- Results first posted 2012-08-31.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT01314703 is a completed phase 4, single-group study sponsored by C. R. Bard, with enrollment of 27. The listed study start was 2011-03 and primary completion was 2011-04. Its primary objective was to measure the antimicrobial effectiveness of ChloraPrep One-Step.
The primary endpoint was mean change in bacterial recovery, in log 10 colony forming units, 10 minutes after a single application relative to baseline. The registry describes 26 qualifying abdominal sites and 25 qualifying groin sites. Numerical outcome estimates and 95% confidence intervals are not reported in the registry record. Although 70% isopropyl alcohol is listed as an intervention, a randomized comparison involving it is not described.
The safety listing records zero subjects affected by serious or other adverse events among 27 at risk; deaths are not reported in the registry record. The record lists one outcome measure and four analyses, but does not detail their methods or multiplicity handling.