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 Point-of-Care RBC Washing to Prevent Transfusion-Related Pulmonary Complications (NCT02094118), a randomized phase 1, phase 2 study. The primary outcome is Biomarkers Associated With Transfusion-Related Acute Lung Injury and Transfusion Associated Circulatory Overload..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02094118 |
| Phase | Phase 1, Phase 2 |
| Condition | Blood Transfusion Complications |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 171 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Mayo Clinic |
| Results posted | Yes |
2. Clinical Question
Population
Patients undergoing cardiac surgery who were predicted to be at high risk for requiring red blood cell transfusion. The registry record identifies blood transfusion complications as the condition of interest.
Intervention
Point-of-care washed red blood cell transfusion: red blood cells washed at the point of care before administration.
Comparator
Standard-of-care red blood cell transfusion: red blood cells administered in the normal fashion.
Primary question
At 18 hours after initiation of the first red blood cell transfusion, how do the groups compare on a panel of biomarkers associated with transfusion-related acute lung injury and transfusion-associated circulatory overload?
The trial asks whether washing red blood cells at the point of care is associated with a different biomarker profile after transfusion than standard-of-care administration. The biomarker panel concerns inflammation, altered coagulation, and endothelial activation, processes described in the registry as playing key roles in lung injury. The primary endpoint is not a single clinical event: it is a panel of measurements reported as units on a scale (pg/ml), with the median and inter-quartile range specified.
The registry also lists clinical outcomes, including duration of mechanical ventilation, duration of oxygen supplementation, Sequential Organ Failure Assessment (SOFA) score, hospital length of stay, and post-transfusion respiratory complications. Their inclusion signals additional questions about respiratory status, organ dysfunction, and hospital course. However, the record does not report comparative results for those outcomes. It therefore does not establish whether the groups differed on the biomarker endpoint or on the listed clinical outcomes.
3. Trial Design
This was a randomized, single-masked, parallel-group trial in Phase 1 and Phase 2. The registry lists an enrollment of 171 and identifies Mayo Clinic as the sponsor. The study began in 2016-01, reached primary completion on 2019-05-30, and has a completed status in the registry record.
The two groups received red blood cell transfusions prepared differently. In the point-of-care washing group, red blood cells were washed at the point of care. In the standard-of-care group, red blood cells were administered in the normal fashion. The registry describes the study population as cardiac surgical patients predicted to be at high risk for requiring red blood cell transfusion. It does not report further eligibility details in the record.
Random allocation is intended, in general, to make treatment groups comparable at the start of a trial on average. It does not guarantee that every baseline characteristic is balanced, particularly in a finite study. The record identifies the allocation as randomized but does not report the sequence-generation method, allocation concealment procedures, or the details of how masking was implemented. “Single” masking is recorded, but the record does not specify which individuals were masked.
The parallel-group structure means that participants were assigned to one group rather than undergoing both transfusion approaches in sequence. The stated primary assessment was 18 hours after initiation of the first red blood cell transfusion. The record lists 10 outcome measures, including the biomarker primary endpoint and several secondary outcomes, but reports 0 analyses. It does not report a detailed statistical analysis plan or the results of group comparisons. The phase designation and completed status describe the trial record; on their own, they do not establish the direction, size, or precision of any treatment effect.
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 | Standard of Care Red Blood Cell Transfusion | Point-of-Care Washed Red Blood Cell Transfusion |
|---|---|---|
| STARTED | 85 | 86 |
| COMPLETED | 73 | 81 |
| NOT COMPLETED | 12 | 5 |
Analysis population for the primary outcome, as defined in the registry: Patients undergoing cardiac surgery who were predicted to be at high risk for requiring red blood cell transfusion.
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 | Standard of Care Red Blood Cell Transfusion | Point-of-Care Washed Red Blood Cell Transfusion | Total |
|---|---|---|---|---|
| Participants analysed | 85 | 86 | 171 | |
| Age, Continuous | years | 66.1 (SD 11.4) | 65.0 (SD 12.1) | 65.6 (SD 11.7) |
| Sex: Female, Male: Female | Participants | 43 | 41 | 84 |
| Sex: Female, Male: Male | Participants | 42 | 45 | 87 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 | 5 | 6 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 81 | 78 | 159 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 3 | 3 | 6 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 2 | 0 | 2 |
| Race (NIH/OMB): Asian | Participants | 1 | 3 | 4 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 14 | 15 | 29 |
| Race (NIH/OMB): White | Participants | 66 | 64 | 130 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 2 | 4 | 6 |
| Region of Enrollment: United States | participants | 85 | 86 | 171 |
6. Primary Endpoint
The registry lists the primary outcome as Biomarkers Associated With Transfusion-Related Acute Lung Injury and Transfusion Associated Circulatory Overload., measured over 18 hours after the initiation of the first red blood cell transfusion..
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | units on a scale (pg/ml) |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is a panel of biomarkers associated with transfusion-related acute lung injury and transfusion-associated circulatory overload. The registry describes the panel as measuring inflammation, altered coagulation, and endothelial activation, which it says play key roles in the pathogenesis of lung injury. These measurements are intended to capture biological responses relevant to pulmonary complications following transfusion.
The specified assessment time is 18 hours after initiation of the first red blood cell transfusion. The unit is reported as units on a scale (pg/ml), and the planned summary is the median with the inter-quartile range. A median describes the middle of an ordered set of measurements; the inter-quartile range describes the spread across the central part of that set. These summaries can be useful when biomarker values are skewed or include extreme observations, although the registry record does not explain why these summaries were selected for this trial.
The endpoint is a panel rather than one named biomarker or one clinical diagnosis. The registry record does not give the component biomarker names, their individual results, or a single prespecified combined score. It also does not report a comparison of the endpoint between groups. Consequently, the endpoint definition explains what investigators intended to measure, but it does not reveal whether the biomarker distributions differed or how precisely any difference was estimated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record sets out a randomized comparison of point-of-care washed red blood cells with standard-of-care red blood cells in a cardiac surgical population at high risk for requiring transfusion. Its primary focus is a biomarker panel assessed at 18 hours after initiation of the first transfusion. Those details define the question, but they are not themselves evidence of a difference between the groups.
The record reports 0 analyses. It gives no group-specific primary-endpoint values, no estimated contrast, and no confidence interval or p-value for the biomarker endpoint. The primary outcome is also described as having several categories or time points and is not reduced to one comparison. Without the underlying endpoint results and a specified comparison, the magnitude and direction of any difference cannot be assessed. The record therefore does not support a conclusion about whether the two transfusion approaches produced different biomarker measurements.
The listed secondary outcomes concern mechanical ventilation, oxygen supplementation, SOFA score, hospital length of stay, and post-transfusion respiratory complications. These outcomes could provide clinical context for the biomarker measurements, but their comparative results are not reported in the registry record. The presence of an outcome in a registry is not evidence that it changed, nor does it show that a particular outcome was statistically significant.
The adverse-event information is descriptive. For serious adverse events, the registry lists 0 affected participants in the standard-of-care group and 7 in the point-of-care washed group; it also reports other adverse events as 0 affected in both groups. Deaths are recorded as 2 and 3, respectively. These entries should not be treated as evidence that the transfusion approach caused the events or deaths. The registry record does not provide event-level narratives, attribution, timing, a statistical comparison, or an adjusted analysis. The listed serious-event terms and percentages do not fill those gaps.
Statistical precision cannot be judged for the primary endpoint because an estimate and its uncertainty are not reported. More generally, a confidence interval describes a range of values compatible with the data and the statistical assumptions used; a narrow interval indicates greater precision than a wide interval. No such interval is reported for the primary comparison. A p-value, even if it were available, would not by itself convey the size or practical importance of an effect. Here, the absence of a reported comparative analysis means neither statistical significance nor lack of statistical significance can be inferred.
Randomization is a strength of the stated design for comparing groups, but it does not substitute for reporting the results or methods needed to interpret them. The record does not report the analysis population, handling of missing measurements, adjustment for baseline values, or multiplicity approach. These omissions matter for judging how the biomarker panel and multiple outcomes were evaluated. The appropriate reading is therefore limited: the registry describes the planned comparison and provides some safety counts, but it does not report enough comparative outcome information to quantify the primary effect or draw a statistical conclusion about it.
9. Statistical Methods Explained
Several statistical ideas help clarify what the registry record does and does not establish. The record describes the design and endpoint, but it reports 0 analyses. No specific statistical test, model, effect estimate, or uncertainty interval for the primary endpoint is reported in the registry record. General explanations of these methods should not be mistaken for methods confirmed as used in this trial.
What does randomization contribute?
In general, random allocation helps reduce systematic differences between groups at the start of a study. If the allocation process is implemented as intended, treatment assignment is not chosen according to a participant’s prognosis. This supports a fair comparison of group outcomes. Randomization does not ensure that groups are identical, and it does not prevent bias arising after assignment, such as incomplete outcome measurement or departures from assigned treatment. The record identifies randomized allocation but does not report the sequence-generation or concealment details, so those procedures cannot be evaluated from the registry record.
Why report a median and inter-quartile range?
The primary endpoint specifies the median and inter-quartile range for biomarker measurements. In general, the median is the central value when observations are ordered. The inter-quartile range describes the spread of the middle half of observations. These summaries are less influenced by unusually high or low values than the mean and standard deviation. That can be helpful for biomarker data, which may have asymmetric distributions. However, the record does not state that skewness motivated the choice, and it gives no group-level medians or inter-quartile ranges to interpret.
A comparison of medians is not automatically the same as a comparison of means, and a difference between group medians does not describe every participant’s response. A valid inferential analysis would need to account for the endpoint’s structure and the trial’s design. The registry record does not identify the statistical procedure selected for the biomarker panel, so no particular test should be attributed to the investigators.
What would an effect estimate and confidence interval show?
In general, an effect estimate quantifies the contrast between groups on a chosen scale. Its interpretation depends on the endpoint and the specified contrast. A confidence interval conveys uncertainty around that estimate under the model and assumptions used. It helps readers assess both the range of effects compatible with the data and the estimate’s precision. The record reports neither a primary-endpoint contrast nor a confidence interval. Thus, readers cannot determine whether the estimated difference, if any, was small or large, or whether the data were precise enough to distinguish among plausible effects.
A p-value addresses how unusual data at least as inconsistent with a specified null hypothesis would be under that hypothesis and the analysis assumptions. It is not the probability that the null hypothesis is true, and it does not measure clinical importance. No p-value for the primary endpoint is reported. Neither a positive nor a null statistical finding can be inferred from the endpoint description or the trial’s completion status.
Why can over-dispersion matter?
In general, over-dispersion occurs when observed variation is greater than a statistical model expects. If a model assumes less variation than the data contain, its uncertainty estimates may be too small and its inferences too confident. Appropriate methods can account for extra variation when the data structure supports that approach. The registry does not report the biomarker distributions or a model, and there is no basis for saying that over-dispersion was present or that a correction was used in this trial. This is a general consideration, not a finding about these data.
How should planning illustrations be read?
A planning illustration based on an observed effect is not an account of the trial’s original design or a measure of observed power. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect defined as a fraction of the observed effect. For time-to-event calculations, the stated quantity is the total number of events; other calculations are expressed as participants per arm. Such illustrations depend on their assumptions and on the effect chosen for planning. The registry record does not report the original sample-size justification, and planning values should not be interpreted as trial outcomes or as proof that the completed trial had adequate precision.
Because there is no reported primary comparison, the central statistical task is not to judge a particular test result. It is to recognize the distinction between an endpoint definition and an analyzed result. The former is present in the record; the latter is not. General statistical concepts can explain how an analysis might be interpreted, but they cannot recover an unreported estimate or replace a documented analysis plan.
10. Multiplicity, Missing Data and Analysis Populations
The primary endpoint is described as a biomarker panel, while the registry also lists several secondary outcomes. Multiple biomarkers, outcome measures, or assessment times can create multiplicity: when many comparisons are made, the chance of at least one apparently unusual result can increase. In general, a statistical plan may address this through a prespecified primary comparison, adjustment procedures, or a structured hierarchy of outcomes. The registry record does not report a multiplicity strategy, identify component biomarker comparisons, or explain how multiple categories or time points were handled. It would therefore be inappropriate to assume that multiplicity was controlled or that every listed outcome had equal confirmatory status.
The record lists 10 outcome measures and 0 analyses. It does not report whether any outcome data were missing, why data might be missing, or how missing measurements were handled. In general, missingness can affect a comparison if the availability of measurements is related to treatment assignment or participant status. Appropriate interpretation depends on knowing how many measurements were available, whether missingness differed between groups, and what assumptions or methods were used. Those details are not reported in the registry record.
The analysis population is also not reported in the registry record. It is therefore unclear from this record whether analyses were intended to include all randomized participants, only participants who received their assigned transfusion, or another defined population. These choices can answer different questions and can affect the interpretation of a treatment comparison. The record does not provide enough information to determine how participants with incomplete endpoint data, protocol deviations, or changes in treatment were addressed.
These are reporting limitations, not proof that the trial lacked a plan or that its analyses were conducted improperly. The registry record simply does not provide the information needed to evaluate multiplicity, missing-data handling, or analysis populations.
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 |
|---|---|---|---|
| Standard of Care Red Blood Cell Transfusion | 0 | 85 | 0.0% |
| Point-of-Care Washed Red Blood Cell Transfusion | 7 | 86 | 8.1% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Standard of Care Red Blood Cell Transfusion | 2 of 85 |
| Point-of-Care Washed Red Blood Cell Transfusion | 3 of 86 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Standard of Care Red Blood Cell Transfusion | 0 of 85 |
| Point-of-Care Washed Red Blood Cell Transfusion | 0 of 86 |
Most frequent serious adverse event terms
| Event term | Organ system | Standard of Care Red Blood Cell Transfusion | Point-of-Care Washed Red Blood Cell Transfusion |
|---|---|---|---|
| hypoxemia | Respiratory, thoracic and mediastinal disorders | 0 of 85 | 2 of 86 |
| Profound Anemia | Blood and lymphatic system disorders | 0 of 85 | 2 of 86 |
| Hyperkalemia | Renal and urinary disorders | 0 of 85 | 2 of 86 |
| Acute respiratory failure | Respiratory, thoracic and mediastinal disorders | 0 of 85 | 1 of 86 |
Serious events with the highest arm-level rate: hypoxemia (2.3%), profound anemia (2.3%), hyperkalemia (2.3%), acute respiratory failure (1.2%).
The registry lists serious adverse events by group. In the standard-of-care group, 85 participants were at risk and 0 were recorded as affected; in the point-of-care washed group, 86 were at risk and 7 were recorded as affected. Other adverse events are listed as 0 affected in each group. The record also reports deaths of 2 in the standard-of-care group and 3 in the point-of-care washed group.
These are descriptive counts, not a causal comparison. The registry record does not report whether events were judged related to the transfusion approach, when they occurred, whether participants experienced more than one event, or how deaths were classified. It also does not provide a statistical comparison or uncertainty intervals for these safety figures. Counts alone do not establish that a difference between groups is attributable to treatment, and 0 recorded affected participants does not prove that an event is impossible.
The listed serious-event terms include hypoxemia, Profound Anemia, Hyperkalemia, and Acute respiratory failure, with percentages reported as 2.3%, 2.3%, 2.3%, and 1.2%, respectively. The registry record does not explain the denominator or provide enough detail to connect each listed term to individual participants or to establish causation. These percentages should be read as registry-reported descriptions, not as comparative risk estimates.
12. What the Result Does, and Does Not, Mean
The record describes a clinically focused randomized comparison: point-of-care washing of red blood cells versus standard-of-care transfusion for cardiac surgical patients predicted to be at high risk for requiring transfusion. Its stated primary endpoint is a biomarker panel assessed 18 hours after initiation of the first transfusion. The panel addresses biological processes related to lung injury, and the listed secondary outcomes include respiratory support, organ failure scoring, length of stay, and respiratory complications.
What the registry record does not provide is the comparative result for that primary endpoint. It reports 0 analyses and does not give group-specific biomarker summaries, an estimated contrast, or a measure of uncertainty. It also does not report comparative results for the listed secondary outcomes. Accordingly, the record cannot show whether the groups’ biomarker measurements or clinical outcomes differed, in which direction a difference might have gone, or how precisely any difference was estimated.
The safety entries provide counts and selected event terms, but they do not establish that an event was caused by either transfusion approach. A count difference is not, by itself, a treatment effect: interpretation would require further details about events, participant follow-up, attribution, and statistical uncertainty. The registry record does not report those details or a formal safety comparison.
The trial’s randomized design is relevant to how a properly reported comparison could be interpreted, but design labels cannot replace outcome data. Nor does a completed status mean that the registry record contains a complete statistical report. A reader should distinguish the question the trial was designed to address from the evidence available in the registry entry. The question concerns whether point-of-care washing changes biomarker or clinical outcomes relative to standard practice; the reported entry does not provide the analyses needed to answer it.
This does not establish that the approaches are equivalent, nor does it establish that one is better or worse. It means that the comparative effect and its precision are not reported in the registry record. The appropriate conclusion is about the limits of the available statistical information, rather than about treatment efficacy.
13. Why This Trial Matters Statistically
This trial is statistically interesting because it links a biological endpoint to a clinical question about transfusion-related pulmonary complications. The primary biomarker panel addresses inflammation, altered coagulation, and endothelial activation, while the secondary outcomes include respiratory support and post-transfusion respiratory complications. Examining such different kinds of outcomes can help distinguish biological response from clinical course, provided the analyses and their uncertainty are reported clearly.
The record also illustrates why endpoint structure matters. A panel of biomarkers is not automatically one outcome, and multiple categories or time points can require explicit decisions about which comparisons are primary and how multiplicity is handled. The record notes that the primary outcome was not reduced to one comparison, while offering no analysis results. Without a defined contrast and reported estimates, readers cannot tell whether a result is consistent across the panel or driven by particular measures.
Randomization makes the intended comparison methodologically important, but statistical interpretation still depends on transparent reporting. An effect estimate, confidence interval, analysis population, and account of missing measurements would help readers assess magnitude, precision, and potential sources of bias. The registry record does not report these elements for the primary endpoint.
The trial therefore matters as a reminder that registering a question and completing a study are distinct from communicating its inferential results. The design and endpoint are identifiable, and the record includes descriptive safety information. Yet the central statistical question remains unanswered in the record because comparative analyses are not reported. That distinction is essential when interpreting clinical trial registries: an outcome’s presence is not the same as an outcome result, and a planned measurement is not evidence of an observed treatment effect.
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 limitation for statistical interpretation is the absence of reported comparative analyses. The registry record lists 0 analyses and provides no primary-endpoint group summaries, effect estimate, confidence interval, or p-value. The primary outcome is described as having several categories or time points and is not reduced to one comparison. This prevents an assessment of the direction, magnitude, or precision of the primary result.
The biomarker panel is not specified by component in the record. The record does not provide the individual biomarker names, their distributions, or information about whether a combined measure was used. It also does not explain how the multiplicity associated with a panel and the listed secondary outcomes was addressed. A reader cannot determine which comparisons, if any, were intended to be confirmatory.
Important analysis details are not reported in the registry record. These include the statistical model or test, the analysis population, baseline adjustment, missing-data handling, and the method used to implement masking. The record identifies single masking but does not state who was masked. It also does not report the randomization sequence-generation or allocation concealment procedures.
Safety information is limited to group-level counts, deaths, and selected serious-event terms with percentages. Event timing, attribution, narratives, overlap between events, and comparative uncertainty are not reported. The listed counts should therefore be treated as descriptive rather than as evidence of causation.
The registry record does not report the original sample-size justification or a detailed statistical analysis plan. Any planning illustration based on an observed effect is distinct from the original design rationale and is not observed power. These limitations constrain what can be concluded from the record; they do not establish that the trial itself lacked analyses or that unreported procedures were not performed.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Point-of-Care RBC Washing to Prevent Transfusion-Related Pulmonary Complications — NCT02094118.
- Registry record last updated 2021-04-06; status last verified 2021-02.
- Results first posted 2021-04-06.
- 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
The registry record describes NCT02094118, “Point-of-Care RBC Washing to Prevent Transfusion-Related Pulmonary Complications,” sponsored by Mayo Clinic. It identifies a randomized, single-masked, parallel-group Phase 1 and Phase 2 trial with an enrollment of 171. The study began in 2016-01, reached primary completion on 2019-05-30, and is marked completed.
The comparison was point-of-care washed red blood cell transfusion versus standard-of-care red blood cell transfusion in cardiac surgical patients predicted to be at high risk for requiring transfusion. The primary endpoint was a biomarker panel measured 18 hours after initiation of the first red blood cell transfusion, summarized using medians and inter-quartile ranges. Listed secondary outcomes included mechanical ventilation duration, oxygen supplementation duration, SOFA score, hospital length of stay, and post-transfusion respiratory complications.
The record lists 10 outcome measures and 0 analyses. Comparative results for the primary endpoint and secondary outcomes are not reported in the registry record. Descriptive serious adverse event counts, other adverse event counts, deaths, and selected serious-event terms are recorded, but they do not establish treatment causation.