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 In Vitro Diagnostic Test for DOAC in Urine (NCT03182829), a registered phase not stated study. The primary outcome is Accuracy of Factor Xa and Thrombin Inhibitors Pads of DOAC Dipstick From Urine Samples.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03182829 |
| Phase | Phase not stated |
| Condition | Anticoagulant Therapy |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 880 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Doasense GmbH |
| Results posted | Yes |
2. Clinical Question
Population
Patients receiving direct oral anticoagulants (DOACs) were evaluated in an outpatient care unit. The registry describes treatment with apixaban, edoxaban, or rivaroxaban in the factor Xa inhibitor group, and treatment with dabigatran in the thrombin inhibitor group. It states that treatment had been ongoing for one week or longer and mentions indications such as non-valvular atrial fibrillation or venous thromboembolism.
Intervention
The diagnostic test was the DOAC Dipstick, an in vitro test applied to urine samples. The study summary describes its performance and handling in an actual point-of-care setting.
Comparator
DOAC Dipstick results were compared with results from liquid chromatography tandem mass spectrometry (LC-MS/MS) on urine samples. The registry describes the comparison as a qualitative analysis.
Primary question
What percentage of DOAC Dipstick responses were correct for the factor Xa inhibitor and thrombin inhibitor pads when assessed against LC-MS/MS results? The primary outcome is described as the accuracy of those pads during urine collection and bioanalytical quantification.
This is a diagnostic-performance question, not a question about whether one treatment is better than another. The record organizes participants by the type of anticoagulant treatment and does not describe a randomized treatment comparison. It lists an enrollment of 880, but does not report how participants were distributed across the two inhibitor groups or how many contributed to the endpoint. The endpoint estimate and its confidence interval are not reported in the registry record, so the size and precision of the observed accuracy cannot be assessed from the record details available for this analysis.
3. Trial Design
The registry identifies NCT03182829 as a completed post-marketing study of the DOAC Dipstick, an in vitro diagnostic test for direct oral anticoagulants in urine. The listed sponsor is Doasense GmbH. The registry enrollment is 880. The study start date is 2018-08-22, and primary completion is listed as 2019-04-09; the status is completed.
The study summary describes an evaluation of test performance and handling in an actual point-of-care testing setting. Urine-sample results from the DOAC Dipstick were compared with results obtained by LC-MS/MS. The arm descriptions distinguish patients receiving factor Xa inhibitors—apixaban, edoxaban, or rivaroxaban—from patients receiving the thrombin inhibitor dabigatran. They also describe treatment for a clinical indication, such as non-valvular atrial fibrillation or venous thromboembolism, for one week or longer.
The registry record does not describe this as a randomized comparison, and it states that allocation is not stated. The inhibitor groups are not a like-for-like control comparison: they represent different drug classes, rather than randomized groups assigned to competing treatments. Consequently, contrasts between those groups should not be read as causal effects of one treatment versus another.
The registry lists one primary outcome measure and one analysis. Further details about recruitment procedures, sample collection procedures, blinding, the handling of repeated samples, or the statistical analysis plan are not reported in the registry record. The record's brief summary includes a publication citation, but the endpoint estimates needed to assess the reported accuracy are not included in the details available for this analysis.
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 | Factor Xa Inhibitor | Thrombin Inhibitor |
|---|---|---|
| STARTED | 467 | 444 |
| COMPLETED | 451 | 429 |
| NOT COMPLETED | 16 | 15 |
Reasons for not completing this period:
| Reason | Factor Xa Inhibitor | Thrombin Inhibitor |
|---|---|---|
| Protocol Violation | 12 | 12 |
| Other | 4 | 3 |
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.
Population: 880 patients with oral intake of a DOAC \>7 days patients are included consecutively if inclusion criteria were not meet patients were excluded if patients present an exclusion criteria patients were included comparability of the two patient groups by statistical analysis of baseline demographic data
| Characteristic | Unit | Factor Xa Inhibitor | Thrombin Inhibitor | Total |
|---|---|---|---|---|
| Participants analysed | 451 | 429 | 880 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 320 | 312 | 632 |
| Age, Categorical: >=65 years | Participants | 131 | 117 | 248 |
| Age, Continuous | years | 67 (18 to 93) | 70 (22 to 91) | 68 (18 to 91) |
| Sex: Female, Male: Female | Participants | 201 | 138 | 339 |
| Sex: Female, Male: Male | Participants | 250 | 291 | 541 |
| Race/Ethnicity, Customized | participants | 451 | 429 | 880 |
| Region of Enrollment: Germany | participants | 451 | 429 | 880 |
6. Primary Endpoint
The registry lists the primary outcome as Accuracy of Factor Xa and Thrombin Inhibitors Pads of DOAC Dipstick From Urine Samples, measured over during urine collection and bioanalytical quantification, any time between August 2018 and April 2019.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage of correct responses |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is titled “Accuracy of Factor Xa and Thrombin Inhibitors Pads of DOAC Dipstick From Urine Samples.” Its unit is percentage of correct responses, and the registry describes the analysis as a mean with a 95% confidence interval. The comparison is between qualitative DOAC Dipstick results and LC-MS/MS results from urine samples. The timeframe is during urine collection and bioanalytical quantification, any time between August 2018 and April 2019.
Accuracy is relevant to a diagnostic evaluation because it describes agreement between test responses and a comparison method. The registry's endpoint description indicates that correct responses are the quantity of interest, but does not report the exact rules used to define a correct response, how the percentage was calculated, or whether any results were combined across drugs or evaluated separately. Those operational details matter: they determine which test outcomes count as correct and what population the estimate represents.
A mean and its confidence interval would ordinarily convey both the central estimate and uncertainty around it. However, neither the endpoint estimate nor the interval limits are reported in the registry record. It is therefore not possible to describe the observed accuracy, compare the precision of the inhibitor-pad results, or assess whether performance varied across drug groups from the record details.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a comparison of qualitative urine-test responses from the DOAC Dipstick with LC-MS/MS results. Its primary outcome is the percentage of correct responses, summarized as a mean with a 95% confidence interval. This framing identifies the intended performance measure, but the record does not report the mean, the confidence interval limits, or the underlying counts. Accordingly, there is no numerical accuracy result to interpret.
The missing estimate also prevents assessment of precision. In general, a confidence interval expresses uncertainty around an estimated quantity under the analysis assumptions; a narrower interval indicates greater precision than a wider one. Without the interval limits, the degree of uncertainty cannot be described. The registry enrollment of 880 does not resolve this limitation: the number enrolled does not establish the number with usable paired test and reference-method results, nor how observations were allocated among the drug groups.
The design is diagnostic rather than therapeutic. The registry's arms correspond to factor Xa inhibitor and thrombin inhibitor treatment groups, and allocation is not stated. The record explicitly notes that these are not like-for-like control arms. Thus, any comparison between the groups would be descriptive unless supported by a suitable analysis and assumptions; it would not, by itself, identify a causal effect of drug class or treatment.
The comparison with LC-MS/MS is central to the endpoint, but the registry description does not provide the classification rules, handling of indeterminate results, or a breakdown of correct and incorrect responses. It also does not give separate sensitivity or specificity estimates. These quantities cannot be inferred from a single overall accuracy description, and none is reported in the registry record.
The study is marked completed, and its primary completion date is 2019-04-09. Completion status and enrollment describe trial conduct, not the magnitude or reliability of diagnostic performance. With the outcome estimate absent, the record supports a description of the study question and design, but not a conclusion about how closely the DOAC Dipstick agreed with LC-MS/MS in the evaluated samples. The record also does not establish performance in settings or populations beyond those described in its summary and arm descriptions.
9. Statistical Methods Explained
What does the endpoint measure?
The registry defines the primary measure as a percentage of correct responses and identifies it as a mean of a continuous measure. In general, a mean describes the average value of a measured quantity across observations included in an analysis. Here, the measure is tied to qualitative DOAC Dipstick results assessed against LC-MS/MS results. The registry does not state the exact classification rule used to decide whether a response is correct, so the detailed construction of the endpoint is not reported in the registry record.
The record identifies a 95% confidence interval as the measure of dispersion. In general, a confidence interval describes uncertainty around an estimate under the statistical model and analysis assumptions. It is not a guarantee that the true value lies within the particular interval, and its interpretation depends on how the data were collected and analyzed. Since neither the interval nor the point estimate is reported in the registry record, precision cannot be evaluated for this endpoint.
Why compare with a reference method?
General: a diagnostic evaluation needs a reference against which test responses can be classified. The study summary identifies LC-MS/MS results from urine samples as the comparator for the qualitative DOAC Dipstick results. Agreement with that comparator is the basis for the stated correct-response measure. The registry does not describe the reference method's thresholds, how paired results were matched, or how discordant or indeterminate findings were handled.
The endpoint is not described as a treatment effect. The factor Xa inhibitor and thrombin inhibitor groups contain patients receiving different drug classes. The record says allocation is not stated and that the arms are not a like-for-like control comparison. Analyses of those groups therefore need to be interpreted as diagnostic assessments within the described treatment categories, not as randomized evidence comparing treatments.
What can a confidence interval add?
General: a point estimate alone gives a central summary, while an interval communicates how much uncertainty remains in that estimate. The interval's width is influenced by factors such as the amount of informative data and variability. In diagnostic work, the relevant information can also depend on the distribution of test responses and reference results. The registry gives no interval limits or response counts, so these aspects cannot be examined for this study from the available record.
The registry's enrollment of 880 is not a substitute for the endpoint denominator. Some enrolled participants may not necessarily have a complete result for every relevant analysis, and the record details do not say how many paired results were analyzed. No denominator for the accuracy estimate, missing-result handling, or analysis population is reported in the registry record.
What does over-dispersion mean generally?
General: over-dispersion occurs when observed variability is greater than a statistical model assumes. If a model does not account for that extra variability, standard errors may be too small and confidence intervals may be too narrow. Whether over-dispersion is relevant depends on the outcome and the analysis model. The registry record does not describe a model or report information that would establish whether over-dispersion was assessed in this study.
How should planning calculations be understood?
General: a sample-size planning illustration asks how much information might be needed under stated assumptions to detect a target effect with a chosen statistical power. Such a calculation is not an observed study result and does not show that the completed study had a particular probability of detecting an effect. The registry record does not report a sample-size justification or the assumptions used to design the trial. No planning illustration can fill in the missing observed endpoint estimate or its precision.
The record lists one primary outcome measure and one analysis. That description does not establish which model, confidence-interval procedure, or analysis population was used. Those statistical details are not reported in the registry record. Without them and the numerical endpoint results, an independent recalculation or assessment of the reported analysis is not possible.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome measure and one analysis. This does not by itself describe the full set of analyses performed, nor does it state whether other endpoints or subgroup comparisons were examined. A multiplicity strategy—such as adjustment of significance thresholds or a prespecified testing hierarchy—is not reported in the registry record. No inference about whether multiplicity was addressed can therefore be made.
The outcome is described as a mean percentage of correct responses with a 95% confidence interval, but the registry record does not give the estimate, interval limits, or response counts. It also does not report how incomplete, indeterminate, or otherwise unavailable test and reference results were handled. The number enrolled is stated as 880, but the number included in the endpoint analysis and the denominator used to calculate the percentage are not reported in the registry record.
The analysis population is not described in the primary outcome details. It is not clear whether all enrolled patients, only patients with paired results, or another defined population contributed to the estimate. The registry also does not report whether observations were excluded, whether repeated samples were possible, or how such observations would have been treated in analysis.
These omissions matter because the endpoint's interpretation depends on who was analyzed, which results were available, and how any missing or ambiguous findings were classified. Without those details, the extent and direction of potential missing-data effects cannot be assessed. A completed status does not supply this information, and the registry record does not provide enough detail to determine how robust the endpoint analysis was to missing results or multiple analyses.
11. What the Result Does, and Does Not, Mean
The registry record describes a completed post-marketing diagnostic evaluation of the DOAC Dipstick in urine samples from patients receiving direct oral anticoagulants. It identifies LC-MS/MS as the comparison method and defines the primary endpoint as the percentage of correct qualitative responses for the factor Xa inhibitor and thrombin inhibitor pads. These details establish the study's central statistical question.
The record does not report the endpoint estimate or its 95% confidence interval. As a result, it does not allow a reader to quantify observed accuracy or its precision. It also does not provide the counts needed to examine the pattern of correct and incorrect responses, and it does not report separate diagnostic measures such as sensitivity or specificity. No result on those measures should be inferred from the endpoint title alone.
The enrollment of 880 and the completed status describe the registered study, but neither is an outcome result. Nor do they establish the number of evaluable paired samples. The record's two inhibitor groups are not randomized control groups; allocation is not stated, and the registry cautions that the arms are not a like-for-like comparison. Differences between those groups cannot therefore be treated as causal treatment effects based on the design description.
In general, diagnostic accuracy estimates are most informative when their definition, analysis population, denominators, uncertainty, and handling of ambiguous or missing results are clear. Several of those details are not reported in the registry record. The available information supports a description of the intended comparison and endpoint, but it does not support a conclusion about the magnitude of diagnostic performance, its precision, or how broadly the findings apply.
12. Why This Trial Matters Statistically
This study raises a useful statistical distinction between evaluating a diagnostic test and comparing treatments. The registry's central question concerns whether qualitative urine-test responses agree with LC-MS/MS results. Its groups are organized by anticoagulant class, not by randomized assignment to competing interventions. Keeping those aims distinct prevents a descriptive diagnostic comparison from being mistaken for evidence about treatment effects.
The endpoint also illustrates why a named accuracy measure is not enough to judge evidence. A percentage of correct responses needs a clear definition and an analysis denominator. Its interpretation is strengthened by reporting the point estimate, confidence interval, and the pattern of results against the reference method. The registry record does not report these numerical or operational details, so the outcome cannot be evaluated quantitatively from the available record.
Enrollment and completion status are useful descriptions of study conduct, but do not substitute for outcome information. The registry enrollment is 880, while the number of paired samples contributing to the primary endpoint is not reported in the registry record. That distinction matters when judging how much information supports a diagnostic estimate.
More broadly, this record shows how registry descriptions can identify a clinically relevant measurement question while leaving uncertainty about analysis choices and results. Reporting the endpoint definition, analysis population, denominators, handling of indeterminate results, and uncertainty would make the statistical evidence easier to assess. In their absence, the appropriate interpretation remains limited to the study's stated purpose and design.
13. 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 most consequential limitation for statistical interpretation is that the primary endpoint estimate and its 95% confidence interval are not reported in the registry record. Without them, observed accuracy and its precision cannot be assessed. The record also does not give the counts of correct, incorrect, or indeterminate responses, or the denominator underlying the percentage of correct responses.
The endpoint's operational definition is incomplete in the available description. The registry names qualitative comparison with LC-MS/MS but does not explain the classification thresholds, how discordant results were treated, or whether results were reported separately by drug or inhibitor pad. These details could affect the meaning of a combined accuracy summary.
The analysis population and missing-data procedures are not reported in the registry record. Although enrollment is listed as 880, the number with paired test and reference results is not stated. It is also unclear from the record how unavailable samples or incomplete measurements were handled. The statistical model and confidence-interval method are not described.
The record identifies factor Xa inhibitor and thrombin inhibitor groups, but does not report group-specific sample sizes or endpoint estimates. Allocation is not stated, and the registry characterizes the arms as not being a like-for-like control comparison. Therefore, group contrasts cannot be interpreted as randomized comparisons.
Finally, the available summary describes an outpatient care unit and an actual point-of-care setting, but does not provide enough information to assess representativeness across other settings or populations. Details of recruitment, blinding, and handling procedures are not reported in the registry record. These limits concern what can be established from the registry description; they do not establish that the study itself lacked those procedures.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: In Vitro Diagnostic Test for DOAC in Urine — NCT03182829.
- Registry record last updated 2022-04-21; status last verified 2022-03.
- Results first posted 2021-05-04.
- 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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17. Record Summary
NCT03182829 is a completed post-marketing study of the DOAC Dipstick, an in vitro diagnostic test for direct oral anticoagulants in urine. The registry lists Doasense GmbH as sponsor and an enrollment of 880. The study started on 2018-08-22, with primary completion on 2019-04-09.
The study summary describes assessment of test performance and handling in a point-of-care setting, comparing qualitative dipstick results with LC-MS/MS results from urine samples. The primary endpoint is the percentage of correct responses for factor Xa inhibitor and thrombin inhibitor pads, summarized as a mean with a 95% confidence interval.
The numerical endpoint estimate, interval limits, analysis denominators, and several analysis details are not reported in the registry record. The arms reflect different inhibitor groups, not a randomized, like-for-like control comparison.