NCT07137429

Brief Summary

Background: Platelets are a type of blood cell that play a critical role in bleeding, forming blood clots, and healing. Researchers want to know more about platelets work in healthy people. They want to look at how platelets clump together, how blood clots, and how genes and proteins work. They also want to study how these processes change over time and how they are affected by factors such diet, exercise, weight, and new health problems. Objective: To study how platelets function in healthy people. Eligibility: Healthy people aged 18 years and older. Design: Researchers will review participants medical history. They will ask about the participant s family history and any drugs they take. Participants will have a clinic visit once every 6 or 7 months for 10 years. Each visit will be 2 to 3 hours. At each visit, participants will have several tests and procedures: A physical exam, including vital signs. Hip and ankle circumference will be measured. Urine collection. Blood tests. About 10 tablespoons of blood will be drawn. Participants will be asked to fast for 10 hours and avoid drugs like aspirin or Advil for 7 days before each draw. Some of the blood may be used for gene studies. Some may be used to create stem cells for research. Stem cells are cells that can be used to make other types of cells. Surveys and questionnaires. Participants will answer questions about habitual activity, diet, smoking, drugs and alcohol, sleep, illness, and other health issues. These surveys may be done online, via email, or by phone.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
400

participants targeted

Target at P75+ for all trials

Timeline
187mo left

Started Mar 2026

Longer than P75 for all trials

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress1%
Mar 2026Sep 2041

First Submitted

Initial submission to the registry

August 21, 2025

Completed
1 day until next milestone

First Posted

Study publicly available on registry

August 22, 2025

Completed
7 months until next milestone

Study Start

First participant enrolled

March 26, 2026

Completed
15.5 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

September 15, 2041

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

September 15, 2041

Last Updated

April 15, 2026

Status Verified

April 9, 2026

Enrollment Period

15.5 years

First QC Date

August 21, 2025

Last Update Submit

April 14, 2026

Conditions

Keywords

PLATELET FUNCTIONPlatelet biology

Outcome Measures

Primary Outcomes (2)

  • Establish and validate technical assays and equipment (e.g. platelet aggregation, hemostasis measurements, methylation, RNA-seq, proteomics and WGS, in vitro iPSC.

    To provide a mechanism for collection of tissue samples from healthy volunteers for use in research studies relating to platelet biology.The goal is to obtain blood samples and corresponding derived information to optimize assays, understand variation in these assays due to different sources of variation, and conduct statistical association studies with appropriate designs including cross-sectional analysis, and longitudinal analyses. Environmental variables may include health reports, anthropometric variables, questions on habits and risk factors and medication during the study.

    10 years

  • Establish normal physiologic mechanisms and platelet-related parameters. How these vary longitudinally and are influenced by variables (e.g., reproducibility, fluctuation with changing diet, exercise, weight and other factors.

    To provide a mechanism for collection of tissue samples from healthy volunteers for use in research studies relating to platelet biology.The goal is to obtain blood samples and corresponding derived information to optimize assays, understand variation in these assays due to different sources of variation, and conduct statistical association studies with appropriate designs including cross-sectional analysis, and longitudinal analyses. Environmental variables may include health reports, anthropometric variables, questions on habits and risk factors and medication during the study.

    10 years

Study Arms (1)

Healthy

Healthy participants, at least 18 years of age

Eligibility Criteria

Age18 Years - 100 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)
Sampling MethodProbability Sample
Study Population

Healthy participants, at least 18 years of age

You may qualify if:

  • In order to be eligible to participate in this study, an individual must meet all of the following criteria:
  • Stated willingness to comply with all study procedures, including fasting at least 10 hours before each blood draw
  • Stated willingness to refrain from aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) for 7 days prior to any visits
  • Age \>= 18 years
  • In good general health as evidenced by self-reported medical history

You may not qualify if:

  • An individual who, by self-report, meets the following criteria will be excluded from participation in this study:
  • Current pregnancy or lactation
  • Active malignancies known, active known auto-immune disease, known major CVD (e.g., heart attack, stroke, venous thromboembolism, heart failure), severe bleeding history, on regular P2Y12 inhibitors or other antiplatelet treatments for a clinical reason, uncontrolled hypertension or diabetes

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

National Institutes of Health Clinical Center

Bethesda, Maryland, 20892, United States

RECRUITING

Related Links

MeSH Terms

Conditions

Thrombosis

Condition Hierarchy (Ancestors)

Embolism and ThrombosisVascular DiseasesCardiovascular Diseases

Study Officials

  • Andrew D Johnson, Ph.D.

    National Heart, Lung, and Blood Institute (NHLBI)

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Jayson J Grey, R.N.

CONTACT

Andrew D Johnson, Ph.D.

CONTACT

Study Design

Study Type
observational
Observational Model
OTHER
Time Perspective
PROSPECTIVE
Sponsor Type
NIH
Responsible Party
SPONSOR

Study Record Dates

First Submitted

August 21, 2025

First Posted

August 22, 2025

Study Start

March 26, 2026

Primary Completion (Estimated)

September 15, 2041

Study Completion (Estimated)

September 15, 2041

Last Updated

April 15, 2026

Record last verified: 2026-04-09

Data Sharing

IPD Sharing
Will share

See DMSP

Shared Documents
STUDY PROTOCOL, ICF
Time Frame
Data will be made available at the time of associated publication and the duration of availability is expected to be indefinite but will ultimately be determined by the NHLBI.
Access Criteria
Clinical and laboratory data will be collected in the electronic data capture system (CTDB) and analyzed using open-source statistical software packages. Some lab-based research data is collected on specialized instruments and custom processing programs are used to summarize/QC. Those scripts will not be shared unless requested.@@@@@@Data sharing for clinical study (PVLMO)@@@Will be via a separate study accession in dbGaP. Summary level data such as GWAS summary statistics or gene expression level means may be deposited in appropriate public repositories such as NCBI GeoDatasets or the NHLBI GRASP GWAS portal.@@@

Locations