Trima Accel® System Post Count Algorithm Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Trima Accel® System Post Count Algorithm Study (NCT02684630), a non-randomized na study. The primary outcome is Donor Postprocedure Platelet Count Following Donation of Single Platelet Product.

2. Clinical Question

The study’s stated purpose was to optimize collected platelet yields for single and double platelet collections while maintaining donor postplatelet count >100,000/µL. The primary endpoint description classifies a procedure as successful when the postprocedure count is ≥ 100,000 platelets/μL and unsuccessful when it is < 100,000 platelets/μL. The blood draw for determining this count was scheduled at least 15 minutes after the end of apheresis.

The registry describes separate groups according to whether donors qualified for single- or double-unit collection. Because allocation was non-randomized, differences between those groups could reflect participant characteristics or collection eligibility as well as the collection category. The record does not establish that the groups were comparable at baseline or that the contrast isolates an effect of the software.

Although the study lists the postprocedure count endpoint, the registry record does not report the number or proportion of successful procedures by group. The primary question is therefore clear from the protocol description, but its observed answer cannot be determined from the results recorded.

3. Trial Design

This was a completed, multicenter study evaluating modified postcount algorithm software on the Trima Accel® System in volunteer blood donors. The registry lists the phase as not applicable, a parallel model, non-randomized allocation, and no masking. Enrollment was 131. The recorded study dates are 2016-01-28 for the start and 2016-05-28 for primary completion.

The two groups were defined by the platelet product collected. Healthy adult volunteer donors who qualified for a single-unit platelet collection were assigned to the Single Platelet Product group description; donors who qualified for a double-unit collection were assigned to the Double Platelet Product group description. In either group, plateletpheresis was performed using the Trima Accel System. The descriptions allow for collection with or without other components.

Because participants were not randomized, the single- and double-product groups should not be treated as interchangeable treatment arms. Qualification for the collection type may be related to participant characteristics, and the registry record does not report whether or how such characteristics were balanced or adjusted for. The comparison is consequently descriptive rather than a controlled estimate of the effect of choosing one collection strategy over another.

The record says that the Full Analysis Set included participants who completed the study and did not meet any protocol exclusion criteria. It also states that a participant could have only one product included in that set, which was used to examine primary and secondary endpoints. The specific exclusion criteria are not reported in the registry record.

The listed intervention is the Trima Accel System, classified as a device. The study title and purpose identify evaluation of modified postcount algorithm software, but the registry record does not give technical details about the modification, software versions, or how the algorithm differed from prior practice. It also does not describe a separate control device or a randomized comparison. The registry reports 2 outcome measures and 2 analyses, but does not give enough detail to identify all analysis procedures or their relationship 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: 131 volunteers signed consent and were enrolled, but 3 were screen fails and therefore did not participate in the study

Overall Study

Analysis population for the primary outcome, as defined in the registry: The Full Analysis Set (FAS) included all participants that completed the study and did not meet any of the protocol exclusion criteria. A participant could only have 1 product included in the FAS. The FAS was used to examine the primary and secondary endpoints.

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: The Safety Population was used to evaluate participant demographics and treatment emergent adverse events (TEAE).

6. Primary Endpoint

The registry lists the primary outcome as Donor Postprocedure Platelet Count Following Donation of Single Platelet Product, measured over The blood draw to determine postprocedure platelet count will occur ≥ 15 minutes after the end of apheresis.

The primary endpoint concerns whether a participant’s platelet count after apheresis met a prespecified threshold. A result of ≥ 100,000 platelets/μL was classified as a successful procedure; a result of < 100,000 platelets/μL was classified as a failure. The endpoint is therefore binary: each included procedure is categorized as success or failure rather than represented by the size of the platelet count change.

The blood draw used to determine the postprocedure count was to occur ≥ 15 minutes after apheresis ended. This timing defines when the endpoint was assessed in relation to the collection. It does not, on its own, tell the reader how much the platelet count changed from before donation, because that change is not the endpoint described in the registry record.

A threshold-based endpoint can make a clinically specified target straightforward to interpret: the count either reaches the stated boundary or does not. At the same time, a binary classification compresses information. Counts just on either side of the threshold are assigned different categories, while two counts on the same side may be quite different in magnitude. The registry record does not report the underlying count distribution or group-specific success results, so the frequency of success and the distance of counts from the threshold cannot be assessed.

The Full Analysis Set was used to examine the primary and secondary endpoints. According to the registry description, it included study completers who did not meet protocol exclusion criteria, with only one product per participant included. The record does not report whether every endpoint observation was available for all members of that set.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is binary because each procedure is categorized as successful or unsuccessful according to a threshold. The success rule is a postprocedure platelet count ≥ 100,000 platelets/μL; the failure rule is a count < 100,000 platelets/μL. For a binary outcome, an analysis commonly reports the number of participants or procedures in each category and the proportion meeting the success rule. Those summaries would show how often the threshold was achieved, but the registry record does not report them for this endpoint.

As a general statistical explanation, a comparison of binary outcomes can be expressed in several ways, including a difference in proportions, a ratio of proportions, or an odds ratio. These measures answer related but not identical questions, and their interpretation depends on the event definition and comparison being made. No primary endpoint effect estimate or analysis measure is reported in the registry record, so none can be attributed to this study.

Uncertainty is also important. A confidence interval accompanies an estimate by conveying the range of values reasonably compatible with the observed data under the model and assumptions used. The width depends, among other things, on the amount of information in the data and the variability of the estimate. A p-value, when reported, assesses compatibility of the data with a specified null model; it is not a measure of effect size or clinical importance. The registry record does not report a primary endpoint confidence interval, p-value, or test method.

The non-randomized allocation requires particular care. Random allocation can, in general, help make comparison groups similar with respect to both measured and unmeasured characteristics, on average. Here, group membership reflects qualification for single- or double-unit collection, not random assignment. Thus a crude difference between groups would not necessarily represent a causal effect of collection category or software. The registry record does not report baseline characteristics, covariate adjustment, matching, or another approach to account for group differences.

The parallel model indicates that the record describes separate groups rather than a crossover sequence in which the same participant receives both collection types. The Full Analysis Set description limits inclusion to participants who completed the study and did not meet protocol exclusion criteria, and allows only one product per participant to enter that set. This defines an analysis population, but it does not reveal how many participants were excluded, whether any endpoint data were missing, or how missing observations were handled. Those details are not reported in the registry record.

The sample-size illustrations use a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. They frame the effect to detect as a stated fraction of the observed effect. These are planning illustrations based on an observed effect, not the study’s own design assumptions and not observed power. A planning calculation describes the sample size associated with chosen assumptions; it does not show the probability that the completed study detected an effect. The registry record does not report a protocol-based sample-size justification.

In general, a planning calculation based on an observed effect should be interpreted cautiously. The observed effect can be uncertain, and a calculation that treats it as fixed does not carry that uncertainty into the planning result. Illustrations at different fractions of an observed effect can help show how a target effect size affects planning, but they do not establish that such an effect is clinically important or that it would be reproduced in another study. No numerical planning results are because the record details do not include those values.

The registry lists 2 outcome measures and 2 analyses. When several outcomes or analyses are examined, multiplicity can matter: repeated testing can increase the chance of at least one apparently unusual result even when the underlying effects are absent. General approaches include prespecifying a primary endpoint, adjusting inference across a family of tests, or treating secondary analyses as exploratory. The registry record does not report a multiplicity strategy, the detailed analysis methods, or whether any interim analyses were planned or performed.

Masking was listed as none. In general, lack of masking can affect how procedures are conducted, how outcomes are assessed, or how events are reported, depending on the setting and endpoint. A platelet count is a laboratory measurement, but the registry record does not state who knew group assignment or how laboratory assessment was handled. It would therefore be inappropriate to assume either that assessment was blinded or that it was influenced by knowledge of group membership.

Finally, the threshold endpoint and a continuous platelet count provide different information. The binary outcome directly answers whether the stated boundary was met. A continuous count could also describe the distribution and magnitude of counts, including how far observations lie from the threshold. The registry record does not report continuous count summaries, so interpretation is restricted to the endpoint definition rather than the distribution of measured counts.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 2 outcome measures and 2 analyses, but does not report their full definitions, the analysis methods, or how the analyses map to the listed outcomes. The primary endpoint is identified as postprocedure platelet-count success after single or double platelet collection. The record also refers to secondary endpoints, but does not describe them in the information available for this analysis.

Multiplicity is relevant whenever several outcomes or statistical tests are considered. As a general principle, testing multiple hypotheses without a planned approach can make isolated nominal findings harder to interpret. Analysts may control the overall error rate, identify one primary analysis and treat others as exploratory, or use another prespecified strategy. The registry record does not report a multiplicity adjustment or a strategy for interpreting multiple analyses. It also does not report whether interim analyses were planned or conducted.

The Full Analysis Set included participants who completed the study and did not meet protocol exclusion criteria. A participant could have only one product included, and this set was used for primary and secondary endpoints. The registry record does not report the number excluded from the set, the reasons for exclusion, the number with missing endpoint measurements, or how missing data were handled. It does not state whether participants with missing counts were excluded, imputed, or addressed through another method.

These omissions matter because the analysis population and missing-data approach can affect both the estimated event frequency and its uncertainty. The completion status of the study does not establish that all enrolled participants contributed an endpoint measurement. Without the analysis details and endpoint results, neither the influence of missing observations nor the consequences of multiple analyses can be assessed.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports serious adverse event counts by product group. In the Single Platelet Product group, 0 serious adverse events were recorded among 65 participants at risk. In the Double Platelet Product group, 0 serious adverse events were recorded among 63 participants at risk. Deaths were recorded as 0 in both groups. No top serious adverse event terms are listed.

For other adverse events, the registry reports 5 affected participants among 65 at risk in the Single Platelet Product group and 2 among 63 at risk in the Double Platelet Product group. These are counts in the registry’s safety categories; the record does not give descriptions of the other events in the available information.

Zero recorded serious events means none were reported in these entries; it does not establish that the risk of a serious event is absent. The study’s non-randomized groups are not a like-for-like safety comparison, and the registry entries alone cannot establish that a group difference is caused by collection type or the device. The record does not report event timing, severity details for other events, relatedness assessments, or a more detailed safety analysis.

12. What the Result Does, and Does Not, Mean

The record establishes that a completed multicenter study evaluated modified postcount algorithm software on the Trima Accel® System in healthy volunteer blood donors. It defines the primary endpoint as a postprocedure platelet count meeting or falling below a stated threshold, with measurement scheduled ≥ 15 minutes after apheresis. It also describes separate groups for single- and double-unit platelet collection and reports safety counts.

Those details explain what the investigators intended to assess, but they do not show the primary outcome. The registry record does not report the group-specific numbers of successful or failed procedures, the observed platelet counts, an estimate of the difference between groups, or a confidence interval. Therefore, the frequency of threshold success and the precision of any comparison cannot be determined from the posted results described in this record.

Even if group outcome estimates were available, the non-randomized allocation would constrain their interpretation. Participants were in groups defined by collection eligibility, and the record does not report a like-for-like control comparison or an adjustment strategy. A difference between groups would not, by itself, isolate the effect of the modified software or establish a causal effect of single versus double collection.

The endpoint is a threshold classification, not a complete description of platelet counts or collection yield. Meeting the threshold would indicate that the count met the criterion recorded for success; it would not, alone, describe the range of counts or the size of any change from before donation. The record does not report yield results with which to assess the study’s stated objective of optimizing yield while maintaining donor postplatelet count.

The safety entries offer limited descriptive information: no serious adverse events or deaths were reported in either group, while other adverse events were recorded in both. They do not establish comparative safety, explain the nature of the other events, or show that any event was caused by the device or collection procedure. The results available in the registry record therefore support a description of the design and recorded safety counts, but not a conclusion about primary endpoint performance or the effect of the modified algorithm.

13. Why This Trial Matters Statistically

This study illustrates why a clear endpoint definition and complete result reporting are both needed for statistical interpretation. The primary endpoint has an explicit threshold: success is a postprocedure platelet count ≥ 100,000 platelets/μL, and failure is a count < 100,000 platelets/μL. That definition makes the intended classification understandable, but the classification alone cannot tell readers how often success occurred. The registry record does not report the primary endpoint counts or estimates.

The design also highlights the difference between a group comparison and a causal comparison. Single- and double-product collections were described in separate non-randomized groups, based on qualification for the collection type. A contrast between those groups could be influenced by who qualified for each type of collection. Without randomization or a reported adjustment strategy, the comparison should not be read as if the groups were equivalent except for the collection category.

Precision is another essential part of interpreting a result. A point estimate, if reported, would need uncertainty information to show how reliably it distinguishes plausible effects. Because the registry record does not report the primary endpoint estimate or its confidence interval, the precision of the intended comparison remains unknown. The study’s completed status and enrollment entry do not fill that gap.

The record also shows why safety counts need context. The serious adverse event and death entries are zero in both groups, while other adverse events are recorded. These counts are useful descriptive information, but sparse counts and non-randomized groups do not by themselves establish comparative safety. Event descriptions and details of assessment are not reported in the record details.

Finally, planning illustrations based on observed effects are not a substitute for a design-based sample-size justification and are not observed power. Their assumptions should be distinguished from the study’s actual conduct. In this study, the registry record does not report a protocol-based sample-size justification, and its listed illustrations are characterized as planning calculations. Separating design, observed results, and planning assumptions is central to sound interpretation.

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 interpreting effectiveness is that the registry record does not report the primary endpoint results. There are no group-specific success or failure counts, rates, effect estimates, or confidence intervals in the record details. Consequently, the primary research question cannot be answered from the posted outcome information.

The non-randomized design is a trial-specific limitation. Donors were grouped according to qualification for single- or double-unit collection, so the groups may differ in ways related to eligibility or other characteristics. The registry record does not report baseline characteristics or an adjustment method that would help address potential group differences. The arms should not be treated as a like-for-like control comparison.

The registry lists no masking. It does not explain who knew the collection group, how postprocedure counts were processed or assessed, or whether any safeguards against assessment bias were used. The endpoint is a count-based classification, but the record does not provide the underlying count distribution or summaries that might show how close results were to the success threshold.

The population is described as healthy adult volunteer donors who qualified for the relevant collection type. The registry record does not establish how findings would apply to people outside this population. It also does not report center-specific results, despite describing the study as multicenter, so variation across participating centers cannot be assessed.

The registry does not report the full secondary endpoint definitions, detailed analysis methods, missing-data handling, or multiplicity strategy. Although it defines the Full Analysis Set, it does not give the number excluded or explain whether endpoint data were missing. The event descriptions for other adverse events are also absent, and no serious adverse event terms are listed. These gaps limit assessment of the endpoint results, analysis robustness, and safety beyond the recorded counts.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Trima Accel® System Post Count Algorithm Study — NCT02684630.
• Registry record last updated 2017-07-12; status last verified 2017-06.
• Results first posted 2017-06-08.
• 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.

18. Record Summary

NCT02684630, titled “Trima Accel® System Post Count Algorithm Study,” was a completed multicenter study of modified postcount algorithm software on the Trima Accel System in volunteer blood donors. The registry lists a parallel model, non-randomized allocation, no masking, phase not applicable, and enrollment of 131. The recorded start date is 2016-01-28 and primary completion date is 2016-05-28.

Participants were described in single- and double-platelet-product groups according to the collection type for which they qualified. The primary endpoint was whether the postprocedure platelet count met the success threshold of ≥ 100,000 platelets/μL, with the blood draw scheduled ≥ 15 minutes after apheresis.

The registry record does not report the primary endpoint results or the detailed analysis methods needed to interpret a group comparison. It records 0 serious adverse events and 0 deaths in both groups, with other adverse events reported in each. Because allocation was non-randomized and the endpoint results are not reported, the recorded information does not establish the effect of the modified algorithm.