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 A Comparison of the RPS Adeno Detector IV to Viral Cell Culture at Detecting Adenoviral Conjunctivitis (NCT00921895), a na na study. The primary outcome is Sensitivity and Specificity of RPS Adeno Detector IV Compared to Cell Culture..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00921895 |
| Phase | NA |
| Condition | Conjunctivitis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 128 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Rapid Pathogen Screening |
| Results posted | Yes |
2. Clinical Question
Population
People with conjunctivitis were the intended population. The registry record lists conjunctivitis as the condition and reports enrollment of 128 participants. It does not report further eligibility details, such as symptom duration, age range, or other participant characteristics.
Intervention
The diagnostic device was the RPS Adeno Detector IV. The arm description says patients with conjunctivitis would be tested with the device. The brief summary describes the test as non-invasive and rapid, and the primary endpoint timeframe is 15 minutes.
Comparator
The intended reference was viral cell culture with confirmatory immunofluorescence, identified as CC-IFA in the registry summary. Polymerase chain reaction was described as a referee for cases in which the device and reference results disagreed. The registry record does not report how many such cases occurred or how they were resolved.
Primary question
The study asked how often the device identified adenovirus-positive cases relative to cell culture and how often it identified adenovirus-negative cases relative to cell culture. These are sensitivity and specificity, respectively, as defined in the registry record. The record specifies that results were to be expressed as percentages of cases with 95% confidence intervals, but it does not report the resulting estimates.
3. Trial Design
The registry record describes a completed device study sponsored by Rapid Pathogen Screening. It lists enrollment of 128 participants, conjunctivitis as the condition, and a single device-testing arm. The arm description says patients with conjunctivitis would be tested with the RPS Adeno Detector IV. Allocation is listed as NA, and the record identifies the design as single-group. This is not a randomized, parallel-group comparison of treatments; cell culture is the diagnostic reference method for assessing test performance.
The brief summary describes the study as a multi-center, prospective, masked clinical trial. However, the registry's masking field is listed as NONE. These statements do not align, and the record does not explain the difference or clarify which procedures, if any, were masked. The actual number of centers and the practical masking arrangements are not reported in the registry record.
The study start is listed as 2009-06, primary completion as 2011-06, and status as COMPLETED. The planned primary endpoint compares the device with cell culture with confirmatory immunofluorescence. Polymerase chain reaction was designated as a referee for discrepant cases, but the record does not describe the prespecified decision process for those cases. The endpoint timeframe is 15 minutes.
The registry lists one outcome measure and 0 analyses. Although the intended design and endpoint are described, the record does not include sensitivity or specificity estimates, confidence interval limits, or participant-level outcome counts. It also does not provide a detailed statistical analysis plan or the number of participants with evaluable results. Consequently, the design can be described from the registry, but the results of the diagnostic comparison cannot be reconstructed from the posted record.
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.
Overall Study
| Stage | Device Testing |
|---|---|
| STARTED | 128 |
| COMPLETED | 128 |
| NOT COMPLETED | 0 |
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 | Device Testing |
|---|---|---|
| Participants analysed | 128 | |
| Age, Customized | years | 43 (5 to 90) |
| Sex: Female, Male: Female | Participants | 76 |
| Sex: Female, Male: Male | Participants | 52 |
| Region of Enrollment: United States | participants | 128 |
6. Primary Endpoint
The registry lists the primary outcome as Sensitivity and Specificity of RPS Adeno Detector IV Compared to Cell Culture., measured over 15 minutes.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage of cases |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “Sensitivity and Specificity of RPS Adeno Detector IV Compared to Cell Culture.” The registry defines sensitivity as the proportion of true positive cases compared with cell culture and specificity as the proportion of true negative cases compared with cell culture. The planned unit is percentage of cases, with a 95% confidence interval, and the timeframe is 15 minutes.
In general, sensitivity describes how often a test is positive among cases classified as positive by the reference method. Specificity describes how often a test is negative among cases classified as negative by the reference method. Reporting both measures addresses distinct aspects of agreement with the reference; a single accuracy summary would not show whether disagreements primarily involved positive or negative classifications. These are general explanations of the statistical concepts, not reported findings from this study.
The reference method matters because the endpoint is defined relative to it. Here, the registry names viral cell culture with confirmatory immunofluorescence, and describes polymerase chain reaction as a referee for discrepant cases. The record does not report the exact rules for combining or adjudicating these tests, the numbers of positive and negative reference cases, or the observed endpoint estimates. It therefore does not establish how precise either estimate was in the completed study.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record establishes the question the study was designed to address: whether the RPS Adeno Detector IV identified adenovirus-positive and adenovirus-negative cases in agreement with viral cell culture with confirmatory immunofluorescence. It also states that polymerase chain reaction would serve as a referee for discrepant cases. These design details describe the intended comparison, but they are not a substitute for the diagnostic results.
No sensitivity estimate, specificity estimate, confidence interval limit, or case count for the primary endpoint is reported in the registry record. The endpoint is described as a percentage with a 95% confidence interval, but the record does not give the values. Thus, the posted information does not show the frequency of agreement with the reference method or how precisely either measure was estimated. The absence of these results should not be interpreted as a low or high value; it means the estimates are not reported in the registry record.
Enrollment was 128, but that total alone cannot establish the precision of sensitivity or specificity. In general, precision depends on the number of cases in the relevant reference categories and on how many test results are evaluable. The registry record does not report those category counts, missing or indeterminate results, or the analysis population. The total enrollment therefore cannot be used to infer the width of the endpoint confidence intervals.
The record lists a single-group device-testing arm and allocation as NA. This means the study should not be read as a randomized comparison between separate treatment groups. The central statistical comparison is between the device and a diagnostic reference applied to cases, not between two randomized groups. The record does not supply cross-classified test results from which diagnostic estimates could be recalculated.
The registry record also contains an unresolved description of masking: its masking field says NONE, while the brief summary calls the study masked. Masking can matter in diagnostic studies if knowledge of one test result influences interpretation of another, but the record does not clarify whether this occurred. The record's mention of a PCR referee suggests a planned approach to discordant results; without the counts and adjudication outcomes, however, the influence of that approach on the endpoint cannot be assessed.
Accordingly, the posted information supports a description of the study question, comparator, endpoint definitions, enrollment, and safety counts. It does not support a conclusion about the device's measured sensitivity or specificity, the uncertainty around those estimates, or the nature of any disagreement with cell culture. No treatment-effect interpretation is appropriate for this single-group diagnostic design.
9. Statistical Methods Explained
The registry record defines a diagnostic accuracy question and specifies sensitivity and specificity as the primary outcome measures. It does not provide the endpoint estimates, underlying result counts, or a detailed analysis plan. The explanations below describe the relevant statistical concepts in general; they should not be mistaken for methods confirmed as having been used in this study.
What do sensitivity and specificity describe?
In general, sensitivity is calculated among cases classified as positive by a reference method: it is the proportion for which the test under evaluation is also positive. Specificity is calculated among reference-negative cases: it is the proportion for which the test under evaluation is negative. Each measure has a different denominator. That distinction is essential when reading diagnostic results: the total number enrolled is not enough to determine either denominator.
For this study, the registry identifies viral cell culture with confirmatory immunofluorescence as the comparator. It says that cell culture defines true positive and true negative cases for the endpoint, and that polymerase chain reaction would be used as a referee for discrepant cases. The record does not report the number of positive or negative reference cases, the device results within those groups, or the number and handling of discrepant cases. Without those details, neither estimate can be recalculated from the registry record.
What does a confidence interval convey?
The endpoint specifies a 95% confidence interval. In general, a confidence interval expresses statistical uncertainty around an estimate under the assumptions of the method used to construct it. A narrower interval indicates greater precision, while a wider interval indicates less precision. It does not show whether the estimate is clinically important, nor does it remove uncertainty about study conduct or the quality of the reference classification. The registry record does not state the interval method or provide its limits, so the precision of the reported endpoint cannot be evaluated.
For a proportion, the amount of information depends particularly on the number of observations in the denominator for that proportion. Sensitivity is based on reference-positive cases and specificity on reference-negative cases. A study can enroll a total of 128 while having different amounts of information for the two measures, depending on the reference classifications and evaluability. The record does not report that breakdown. This general point explains why the enrollment total alone is insufficient to assess endpoint precision.
How should discrepant results be considered?
The registry summary describes polymerase chain reaction as a referee for discrepant cases. In general, a referee test can help investigate disagreements between a device and a reference method. The analysis can depend on the prespecified rule: for example, whether the initial reference classification is retained, replaced, or adjudicated using additional information. No such rule, count of discrepant cases, or final classification is reported in the registry record. The effect of the referee procedure on sensitivity and specificity therefore cannot be determined.
What does the design imply for statistical comparisons?
The registry identifies the model as single-group and allocation as NA. In general, a single-group diagnostic study evaluates test results against a reference rather than estimating a randomized between-group treatment contrast. It would therefore be inappropriate to interpret the study as a trial comparing two treatment arms. The listed device-testing arm does not create a separate randomized control group; cell culture functions as the diagnostic comparator.
The record says the outcome measure uses a 95% confidence interval but does not identify a statistical test, interval construction, handling of indeterminate test results, or analysis population. It also lists 0 analyses. These omissions mean that the precise computational approach and the set of participants contributing to any estimate are not reported in the registry record.
What are the planning illustrations?
Any sample-size planning illustration associated with this record should be distinguished from the study's actual design and results. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. The record explicitly characterizes this as a planning illustration computed from the observed effect, not the trial's own design. Its two-arm assumptions do not match the listed single-group diagnostic design. Such illustrations are planning quantities, not observed power, and they do not establish how the study was planned or whether the endpoint was adequately precise. The record does not report the trial's own sample-size justification.
In general, a planning calculation depends on assumptions about the target effect, variability, design, and statistical criterion. If those assumptions do not reflect the actual study, the resulting planning values should not be treated as evidence about the completed study. Here, no endpoint estimates or confidence interval limits are reported, so the reader cannot assess the observed effect or precision from the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one outcome measure: sensitivity and specificity of the RPS Adeno Detector IV compared with cell culture. It does not describe a multiplicity adjustment, a hierarchy between sensitivity and specificity, or a distinction between primary and secondary hypotheses. The record also lists 0 analyses. It is therefore not reported in the registry record whether any multiplicity strategy was prespecified or applied.
In general, multiplicity becomes relevant when several statistical claims are evaluated, because repeated testing can increase the chance of at least one apparently notable result under a null hypothesis. Sensitivity and specificity are distinct measures, even when they are reported together as one outcome measure. Without an analysis plan, it is not possible to determine how the study treated them for inferential purposes. No p-values or other inferential results are reported in the registry record.
The registry record does not report missing, indeterminate, invalid, or unevaluable test results. It also does not state whether all enrolled participants were included in the endpoint analysis, whether exclusions occurred, or how missing results would be handled. The analysis population and the number contributing to each endpoint are not reported in the registry record. These omissions matter because estimates based on only evaluable cases may not describe all enrolled participants if exclusions or missing results are related to test performance.
In general, missingness can affect both the size and interpretation of a diagnostic accuracy estimate, especially when the reasons for unavailable results are related to participant characteristics or test outcomes. The record does not provide enough detail to assess whether such concerns arose. It also does not specify how discrepant results involving the PCR referee were incorporated into the analysis. Thus, neither the impact of missing results nor the handling of discordance can be evaluated from the posted information.
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 |
|---|---|---|---|
| Device Testing | 0 | 128 | 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 |
|---|---|
| Device Testing | 0 of 128 |
The registry reports 128 participants at risk for serious adverse events and 0 with a serious adverse event in the Device Testing group. It also reports 128 at risk for other adverse events and 0 with an other adverse event. Deaths are listed as null, and the registry does not provide serious adverse event terms.
These counts are descriptive safety entries for the device-testing group. They are not a randomized safety comparison, because the record identifies a single-group design and lists allocation as NA. The record does not provide event definitions, follow-up details, severity grading beyond the serious-event category, or information about how adverse events were collected. It also does not explain the null entry for deaths, so it should not be read as a reported count of zero deaths.
In general, a recorded count of zero means that no events are listed in that category in the registry entry; it does not establish that an event is impossible or that all types of harm were comprehensively measured. The record's adverse-event counts should therefore be read narrowly: it records 0 serious adverse events and 0 other adverse events among the stated 128 at risk in this group, while broader safety details are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The study addresses a practical statistical question about diagnostic classification: how closely the RPS Adeno Detector IV identifies adenovirus-positive and adenovirus-negative cases relative to viral cell culture with confirmatory immunofluorescence. The registry also describes PCR as a referee for discrepant cases. Its endpoint definitions make clear that the planned assessment involved both sensitivity and specificity, rather than a single undifferentiated measure of agreement.
What the posted record does not establish is the observed performance. It contains no sensitivity or specificity estimate, no 95% confidence interval limits, and no case-level counts for the reference-positive and reference-negative groups. It therefore cannot show the frequency of correct or discordant classifications, nor the precision of either endpoint. Enrollment of 128 does not resolve those gaps because the relevant endpoint denominators are not reported.
In general, diagnostic accuracy estimates describe agreement with a defined reference under the study's procedures. They do not, by themselves, answer every question about the value of a test in other settings. The result can depend on the population studied, the way cases are selected, the reference method, and how discordant or missing results are handled. The registry record does not provide enough detail about these features to assess their influence in this study.
The record supports describing the intended endpoint and design, not declaring that the device did or did not meet a performance standard. It gives no threshold for acceptable sensitivity or specificity and reports no actual estimate to compare with any such threshold. There is likewise no randomized treatment comparison or clinical outcome result to interpret. A completed status indicates the study's registry status, but it does not supply the missing endpoint findings.
The appropriate reading is therefore limited: the registry describes a completed single-group diagnostic evaluation with enrollment of 128 and a stated reference method, but its posted results do not permit conclusions about measured sensitivity, specificity, or their uncertainty. Any stronger interpretation would require results and methodological details not reported in the registry record.
13. Why This Trial Matters Statistically
This study is statistically notable because it illustrates that a diagnostic question is not the same as a treatment comparison. The registry lists a single device-testing group and allocation as NA. Its central quantities are sensitivity and specificity relative to a reference method, not a difference between randomized arms. Reading the design correctly helps prevent treatment-trial assumptions from being applied to a diagnostic accuracy study.
The endpoint also highlights why denominators matter. Sensitivity and specificity use different reference-defined groups, so the total enrollment alone cannot reveal the information available for either estimate. The registry reports enrollment of 128 but does not report the numbers of reference-positive or reference-negative cases or the endpoint confidence intervals. This makes the distinction between a study's total size and the effective information for a particular diagnostic measure especially important.
The planned use of PCR as a referee for discrepant cases raises another general statistical issue: the classification rule is part of the measurement process. In general, changing how discordant results are adjudicated can change the endpoint numerator or denominator. The registry record does not report the adjudication rule or the number of discordant cases, so this aspect cannot be evaluated.
Finally, the mismatch between the registry's masking field, listed as NONE, and the brief summary's description of a masked study shows why design fields and narrative descriptions should be read together. The record does not reconcile them, leaving uncertainty about masking procedures. More broadly, a clearly specified design and complete outcome reporting are both necessary for readers to interpret diagnostic estimates. This record states the statistical question but does not report the estimates needed to answer it.
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 principal limitation for interpreting this specific study is that the registry record does not report the primary endpoint results. Sensitivity and specificity are defined, and 95% confidence intervals are specified, but neither estimates nor interval limits are posted. No cross-classified device and reference results are reported. Consequently, the diagnostic performance and its precision cannot be assessed from the record.
The enrollment total of 128 is reported, but the numbers of reference-positive and reference-negative cases are not. The record also does not state how many participants had evaluable results, whether results were missing or indeterminate, or what analysis population was used. These details are needed to understand the denominators and potential exclusions for each endpoint.
The registry describes PCR as a referee for discrepant cases without reporting the prespecified adjudication rule, the number of discrepancies, or the final classifications. This leaves uncertainty about how discordance contributed to the planned estimates. The actual number of study centers is also not reported, despite the brief summary describing a multi-center trial.
Masking is unclear: the registry field lists NONE, whereas the brief summary describes a masked trial. The record does not explain that difference or specify who, if anyone, was masked. It also does not report the trial's own sample-size justification or detailed statistical analysis plan. The sample-size planning assumptions described in the record are explicitly illustrative and do not establish the design rationale for this single-group study.
Finally, the safety entry provides event counts but little context about collection, definitions, or follow-up; deaths are listed as null. These limitations concern what can be interpreted from the registry record and do not establish that the omitted procedures or information were absent from the study itself.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Comparison of the RPS Adeno Detector IV to Viral Cell Culture at Detecting Adenoviral Conjunctivitis — NCT00921895.
- Registry record last updated 2021-11-03; status last verified 2021-11.
- Results first posted 2012-08-24.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
This completed registry record describes a single-group diagnostic study of the RPS Adeno Detector IV in people with conjunctivitis. Enrollment was 128. The intended primary outcome was sensitivity and specificity relative to viral cell culture with confirmatory immunofluorescence, expressed as percentages with 95% confidence intervals; the timeframe was 15 minutes. Polymerase chain reaction was described as a referee for discrepant cases.
The record lists allocation as NA, masking as NONE, one outcome measure, and 0 analyses. Its brief summary describes a prospective, multi-center, masked study, but the record does not resolve the difference in masking descriptions or report the number of centers. The primary endpoint estimates, confidence interval limits, analysis population, and details of discrepant or missing results are not reported in the registry record.
For safety, the record lists 0 serious adverse events and 0 other adverse events among 128 at risk in the device-testing group; deaths are listed as null. The registry status is COMPLETED.