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 HOP-2A - Intratesticular Hormone Levels (NCT00756561), a registered phase not stated study. The primary outcome is Intratesticular Hormones in Normal Men.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00756561 |
| Phase | Phase not stated |
| Condition | Healthy, Male Infertility, Prostate Disease |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Washington |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns healthy young men. The registry record lists an enrollment of 10 and identifies the primary endpoint population as per protocol. Its conditions also include Healthy, Male Infertility, and Prostate Disease; those labels do not establish that participants had infertility or prostate disease.
Intervention
This was an investigational study using fine needle aspiration to examine hormones present in healthy male testicles. The brief description does not specify a treatment intervention, dose, or treatment schedule.
Comparator
The record does not describe randomized treatment arms or a like-for-like control comparison. It mentions average values between the right and left testis for each subject and serum hormone concentration, but does not present these as randomized groups.
Primary question
The primary endpoint is titled “Intratesticular Hormones in Normal Men.” It concerns hormone concentrations in the testis and serum, summarized using a median and inter-quartile range in ng/mL. The stated timeframe is 6-weeks. The registry record does not report the resulting concentrations, so the size or pattern of any observed hormone levels cannot be described from this record.
The study’s stated purpose is descriptive: to find out what hormones are present in healthy male testicles using fine needle aspiration. The endpoint description says that the measure is an average between the right and left testis for each subject and serum hormone concentration in 10 normal men. This describes the intended measurements, not an estimated treatment effect. The record does not identify a causal comparison, nor does it report results with which to assess a difference between testicular and serum concentrations. The clinical question is therefore about measuring hormone levels in the study population, rather than comparing the efficacy of assigned treatments.
3. Trial Design
The registry identifies HOP-2A as a completed study, sponsored by the University of Washington, with the title “Intratesticular Hormone Levels.” Its official title is “Intratesticular Hormone Levels in Healthy Young Men.” The recorded study start is 2008-09 and the primary completion is 2009-01. Enrollment is 10. The study is classified as “other,” rather than as a randomized comparison.
The brief summary describes an investigational study using fine needle aspiration to find out what hormones are present in healthy male testicles. The primary endpoint refers to intratesticular hormones in normal men and includes serum hormone concentration. The endpoint description refers to an average between the right and left testis for each subject. The population is identified as per protocol, and the timeframe is 6-weeks. These details describe the measurements and endpoint population; they do not establish a treatment assignment or a control group.
The registry record does not state an allocation method. It also does not describe arms as a like-for-like control comparison. Consequently, the study should not be read as a randomized trial of competing interventions. The record does not report further details about how participants were recruited, how aspiration was performed, or the timing of sample collection beyond the stated endpoint timeframe. Those protocol details are not reported in the registry record.
The “other” classification is not reduced to one comparison. The record lists one outcome measure and zero statistical analyses. It reports no hormone estimates, uncertainty intervals, or inferential test results. The endpoint specifies a median and inter-quartile range, but the numerical values for those summaries are not reported in the registry record. The listed enrollment and endpoint population should also be distinguished: enrollment is 10, while the endpoint is described as per protocol. Further details about who was included in that analysis population are not reported in the registry record.
Planning illustrations are not the study’s own design rationale or evidence of achieved statistical power. The registry record does not report the protocol’s sample-size justification, allocation plan, or statistical analysis plan. The study’s descriptive objective and missing numerical results limit what can be inferred about the measured hormone concentrations.
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: 15 screened, 3 did not meet inclusion criteria (2 for abnormal semen parameters, 1 for abnormal liver function), 1 decided not to enroll, and 1 did not complete study procedures because of study end. Data analysis was performed on the first 10 of 11 subjects completing procedures.
Overall Study
| Stage | Healthy Normal Males |
|---|---|
| STARTED | 10 |
| COMPLETED | 10 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: per protocol
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 | Healthy Normal Males |
|---|---|---|
| Participants analysed | 10 | |
| Age, Continuous: Between 18 and 50 years | years | 23 (21 to 32) |
| Sex/Gender, Customized: Male | participants | 10 |
| Body Mass Index (BMI) | kg/m^2 | 25.9 (23.4 to 28.7) |
| Sperm concentration | millions/mL | 75 (28 to 133) |
| Luteinizing Hormone (LH) | IU/L | 3.7 (2.1 to 5.4) |
| Follicle Stimulating Hormone (FSH) | IU/L | 1.8 (1.4 to 2.5) |
| Serum Testosterone (T) | ng/mL | 3.0 (2.3 to 3.9) |
| Serum Dihydrotestosterone (DHT) | ng/mL | 0.20 (0.12 to 0.24) |
| Serum Estradiol (E2) | ng/mL | 0.025 (0.019 to 0.029) |
| Testis volume | mL | 25 (20 to 25) |
6. Primary Endpoint
The registry lists the primary outcome as Intratesticular Hormones in Normal Men, measured over 6-weeks.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | ng/mL |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “Intratesticular Hormones in Normal Men.” It reports concentration in ng/mL and identifies the summary statistic as a median with an inter-quartile range. The description refers to an average between the right and left testis for each subject, as well as serum hormone concentration, in 10 normal men. The endpoint population is per protocol, and the stated timeframe is 6-weeks.
These measurements are intended to describe hormone concentrations in the studied population. A median gives the central position of the observed values when they are ordered; the inter-quartile range describes the spread across the middle portion of those values. As a general statistical explanation, this pair of summaries can communicate both a typical value and variability without requiring the distribution to be symmetric. It does not, by itself, show whether levels differ between groups or establish a causal effect.
The record does not give numerical hormone concentrations or inter-quartile ranges. It also does not identify each hormone measured in the endpoint description. Therefore, the intended measurement and summary approach can be described, but the magnitude and variability of the observed concentrations cannot be assessed from the registry record. The use of the word “average” for the right and left testis describes a within-subject measure; the record does not provide further computational detail about how that measure was formed for each hormone.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a small descriptive study with enrollment of 10 and a per-protocol primary endpoint. Its stated purpose is to identify hormones present in healthy male testicles using fine needle aspiration. The primary endpoint concerns intratesticular and serum hormone concentrations, expressed in ng/mL and summarized by a median and inter-quartile range. These details establish what the study set out to measure, but they do not provide the measurements themselves.
No numerical hormone results are reported in the registry record. In particular, it does not report medians, inter-quartile ranges, participant-level observations, or comparisons between testicular and serum concentrations. No effect estimate, confidence interval, or p-value is listed, and the record reports zero statistical analyses. There is therefore no basis in the posted results to characterize the magnitude, direction, or precision of hormone concentrations or any difference between measurement locations.
The enrollment figure is not a measure of precision on its own. As a general statistical point, the precision of an estimate depends on the observed data and their variability, as well as the number of observations contributing to the estimate. Without the reported hormone values and their dispersion, the precision of the endpoint cannot be evaluated. The stated median and inter-quartile range would help describe the observed distribution if their values were available, but the summary-statistic labels alone do not show how concentrated or variable the measurements were.
The study is classified as “other,” and the registry’s design note says it is not a randomized comparison; allocation is not stated and arms are not a like-for-like control comparison. The endpoint description mentions right and left testis averages and serum concentrations, but this is not evidence of a randomized allocation or a controlled treatment contrast. Any interpretation should remain descriptive rather than causal. The registry does not report a comparison analysis that would quantify a difference between these measurements.
The endpoint applies to a per-protocol population, while enrollment is recorded as 10. The record does not explain the criteria for inclusion in that population or whether all enrolled participants contributed data. Its adverse-event record lists 11 participants at risk for serious events, a denominator that differs from the enrollment figure. The registry does not explain that discrepancy. These figures concern safety reporting and do not fill the gap in the primary hormone results.
Overall, the posted information establishes the study’s objective, endpoint summary method, and general design classification. It does not establish what hormone concentrations were observed, how precisely they were estimated, or whether any measurements differed. Those conclusions require results that are not reported in the registry record.
9. Statistical Methods Explained
The endpoint is described as a median with an inter-quartile range, with concentrations in ng/mL. The endpoint description refers to an average between the right and left testis for each subject and serum hormone concentration. The population is per protocol, and the timeframe is 6-weeks. The registry record does not provide numerical results or details of the analysis procedure beyond those descriptions.
What does the median describe?
As a general statistical explanation, the median is the middle value after observations are ordered. It can be useful when a distribution is skewed or contains values far from the center, because such values have less influence on the median than on the arithmetic mean. The inter-quartile range describes the spread of the middle half of ordered observations. These statistics summarize the location and variability of measured values; they do not indicate whether a value is clinically important or whether one measurement differs from another.
The registry’s use of “average” for the right and left testis is distinct from the median summary. The description indicates a per-subject measure combining right- and left-testis values, while the endpoint identifies the median and inter-quartile range as summary statistics. The exact computation for each hormone is not reported in the registry record. The record also does not list the individual hormones or the actual values, so the summaries cannot be independently interpreted or checked.
What would a confidence interval add?
In general, a confidence interval expresses uncertainty around an estimate under a specified statistical method. It helps readers distinguish the estimated value from the range of values compatible with the data and method. No confidence interval is reported for this endpoint. Without numerical results and an interval estimate, the precision of any hormone estimate cannot be assessed from the registry record. A median and inter-quartile range would describe the observed distribution, but would not by themselves provide a confidence interval for the median.
What does the design classification imply?
The record classifies the study as “other” and says it is not a randomized comparison. Allocation is not stated, and the arms are not described as a like-for-like control comparison. This matters because random assignment, when used, supports a particular kind of causal comparison by reducing systematic differences between assigned groups. The registry does not establish that such an assignment occurred. Its endpoint description includes testicular and serum measurements, but that alone does not create a randomized intervention contrast.
As a general concept, over-dispersion occurs when observed variability is greater than a statistical model expects. In that situation, a model that assumes less variability may report uncertainty that is too small. The registry record does not report a model-based analysis, count outcome, or over-dispersion assessment for this endpoint, so over-dispersion is not an identified feature of the reported analysis. More generally, the choice of a statistical model should follow the outcome type, design, and observed distribution; those details are not described sufficiently to identify a model used.
How should the planning illustration be understood?
The sample-size assumptions describe a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The assumed effect to detect is a stated fraction of the observed effect. These are assumptions for an illustration, not a report of the trial’s own design rationale. The registry record does not report the protocol’s sample-size justification or a randomized two-arm allocation. The illustration therefore should not be interpreted as observed power or as proof that the study was designed to detect a particular difference. No calculated planning figures are reported in the registry record.
In general, a significance level is a threshold used in a specified testing procedure; it does not describe the probability that a study conclusion is correct. A normal approximation is a mathematical simplification whose suitability depends on the data and analysis. Equal allocation is an assumption about how participants would be divided for the planning exercise. Those assumptions do not establish that the study used a hypothesis test, had two assigned arms, or followed that analysis plan. The statistical analysis plan is not reported in the registry record.
The record reports zero statistical analyses. It does not provide inferential results, variance estimates, missing-data methods, or a detailed account of endpoint derivation. Thus, the statistical methods that can be identified are limited to the stated descriptive summaries and endpoint description. Any more specific claim about estimation, adjustment, testing, or model fitting would go beyond the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and zero statistical analyses. The primary endpoint is described using a median and inter-quartile range, but its numerical results are not reported in the registry record. A single listed outcome measure does not establish that only one statistical question was considered in the protocol; further details about planned outcomes and analyses are not reported in the registry record.
As a general statistical issue, multiplicity arises when multiple hypotheses or outcomes are tested. The more tests conducted, the greater the chance that at least one result appears statistically notable by chance if no adjustment or prespecified approach is used. Whether this issue applied to the planned analysis cannot be determined. The registry record does not report an analysis plan, multiplicity adjustment, or interim analysis plan.
The endpoint population is identified as per protocol. The record does not describe the criteria used to define that population or state how many participants contributed to the primary endpoint. Enrollment is 10, but that number alone does not reveal whether endpoint data were available for every enrolled participant. Reasons for any missing measurements and methods for handling missing data are not reported in the registry record.
As a general principle, missing-data methods should be considered in relation to why measurements are missing and what assumptions the method makes. No such assumptions or procedures are reported. The registry also does not identify an intention-to-treat population or another analysis population beyond the per-protocol label. These omissions limit assessment of how the analysis population was formed and whether the endpoint summaries represent all enrolled participants.
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 |
|---|---|---|---|
| Healthy Normal Males | 0 | 11 | 0.0% |
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 |
|---|---|
| Healthy Normal Males | 4 of 11 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Healthy Normal Males |
|---|---|---|
| upper respiratory infection | Respiratory, thoracic and mediastinal disorders | 2 of 11 |
| discomfort at lidocaine injection site | Reproductive system and breast disorders | 1 of 11 |
| bruised ribs | Musculoskeletal and connective tissue disorders | 1 of 11 |
The safety record lists the group “Healthy Normal Males” with 11 participants at risk for serious adverse events and 0 participants affected by serious adverse events. It also lists 11 participants at risk in the other adverse-event category, with 4 affected. The number of deaths is not reported in the registry record. No serious adverse-event terms are listed.
These counts are safety summaries, not hormone endpoint results. The record lists enrollment as 10, whereas the safety denominator is 11. The reason for this difference is not reported in the registry record; the denominator should therefore be quoted as recorded rather than reconciled by assumption. The record does not explain the meaning or scope of the other adverse-event category in further detail, so the count of 4 should not be interpreted as a specific type or severity of event.
A count of 0 affected by serious adverse events means none are recorded in that category for the stated group and denominator. It does not establish that no adverse events of any kind occurred, since the separate other category lists affected participants. Nor does a zero count establish that an event is impossible or that the study could rule out uncommon events. With no listed serious-event terms and no death count, the safety information available for interpretation is limited to the registry’s reported counts.
12. What the Result Does, and Does Not, Mean
The record describes a completed investigation of hormone levels in healthy young men. Its stated purpose is to identify hormones present in healthy male testicles using fine needle aspiration. The primary endpoint concerns intratesticular hormones and serum hormone concentration, with concentrations expressed in ng/mL and summarized by a median and inter-quartile range. The endpoint description refers to an average between the right and left testis for each subject.
These details show what the study was intended to measure and how the endpoint was described. They do not show the hormone concentrations observed. The registry record reports no numerical endpoint results and zero statistical analyses. It therefore does not support a conclusion about the magnitude or variability of hormone levels, nor about whether testicular and serum measurements differed. No effect estimate or uncertainty interval is reported.
The study is not described as a randomized comparison, and allocation is not stated. Thus, the endpoint information should not be treated as evidence of a randomized treatment effect. Measuring concentrations in different locations may support descriptive characterization, but the record does not report a comparative analysis or establish a causal contrast.
The enrollment of 10 provides context about the size of the study, but does not by itself show the precision of an estimate. The primary analysis population is labeled per protocol, and details about inclusion, missing measurements, and data handling are not reported in the registry record. The safety count of 11 at risk also differs from the enrollment figure, with no explanation recorded. These gaps further limit interpretation of the posted information.
The result that can be stated is therefore narrow: the registry records a completed study designed to characterize hormone concentrations, with a specified descriptive endpoint and a per-protocol population. The numerical hormone findings and their statistical uncertainty are not reported in the registry record. This does not establish that hormone levels were high, low, changed, or different across measurement locations, and it does not establish a treatment benefit or lack of benefit.
13. Why This Trial Matters Statistically
This study illustrates an important distinction between a stated measurement objective and a report of statistical results. The registry identifies the endpoint, units, summary method, population, and timeframe. Those elements help readers understand what the investigators intended to quantify. However, without the numerical concentrations or their dispersion, readers cannot assess the observed distribution or the precision of an estimate.
It also illustrates why design classification matters. The record describes an “other” study, not a randomized comparison, and allocation is not stated. Intratesticular and serum measurements are named in the endpoint description, but naming different measurement sources does not by itself establish a controlled or causal contrast. Statistical interpretation needs to follow the design that is actually documented, not infer a comparison that the record does not describe.
The distinction between enrollment and analysis population is also relevant. The record lists enrollment of 10 and identifies the primary endpoint population as per protocol, without further information about eligibility for that analysis or endpoint completeness. Safety reporting lists 11 at risk, a difference that is not explained. These registry entries show why denominators and population definitions should be examined alongside outcome summaries.
Finally, the record reports no statistical analyses and no numerical primary outcome results. A named median and inter-quartile range indicate a descriptive approach, but they are not substitutes for the values themselves. This makes the boundary between what is known and what remains unreported especially clear: the study’s aim and endpoint are documented, while the statistical findings needed to characterize the measured hormone levels are not reported in the registry record.
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 numerical primary outcome results. Although the endpoint specifies concentrations in ng/mL and a median with an inter-quartile range, the actual summaries are not reported in the registry record. The record also reports zero statistical analyses. As a result, the observed hormone levels, their variability, and the precision of any estimate cannot be assessed.
The endpoint description refers to the average between the right and left testis for each subject and serum hormone concentration, but it does not name the specific hormones or provide further detail about how each measurement was processed. The study timeframe is listed as 6-weeks, but the timing of the individual sample collections is not described beyond that. Further assay and measurement details are not reported in the registry record.
The primary endpoint population is labeled per protocol, while enrollment is 10. The record does not provide the per-protocol inclusion criteria, the number contributing endpoint data, or reasons for missing measurements. The safety record lists 11 participants at risk, which differs from enrollment, and does not explain the denominator. The reason for these differences is not reported in the registry record.
The study is classified as “other,” with no randomized comparison described and allocation not stated. Accordingly, the record does not support an interpretation as a randomized treatment comparison. The protocol’s sample-size justification, statistical analysis plan, and any planned interim analyses are not reported in the registry record. These limitations are specific to the available description and results; they leave the study’s measurement objective identifiable but its numerical statistical findings unavailable.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: HOP-2A - Intratesticular Hormone Levels — NCT00756561.
- Registry record last updated 2016-06-13; status last verified 2016-05.
- Results first posted 2013-07-19.
- 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
HOP-2A is a completed study sponsored by the University of Washington. It enrolled 10 and is described as an investigation of hormone levels in healthy young men using fine needle aspiration. The primary endpoint, “Intratesticular Hormones in Normal Men,” concerns intratesticular and serum hormone concentrations in ng/mL, summarized by a median and inter-quartile range. The endpoint population is per protocol, with a stated timeframe of 6-weeks.
The record classifies the study as “other,” does not describe a randomized comparison, and does not state allocation. It lists one outcome measure and zero statistical analyses. Numerical hormone results, the statistical analysis plan, missing-data procedures, and further details of the per-protocol population are not reported in the registry record.
The safety record lists 0 participants affected by serious adverse events among 11 at risk, and 4 affected in the other adverse-event category among 11 at risk. The death count is not reported in the registry record. The reason the safety denominator differs from enrollment is also not reported.