An observational study in Thrombosis, sponsored by National Heart, Lung, and Blood Institute (NHLBI). Recruiting at 1 site in United States. Open to participants aged 18 Years to 100 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-31.
Sponsored by National Heart, Lung, and Blood Institute (NHLBI) · Observational
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.
Study Description:
This study will serve to provide tissue samples from healthy volunteers for mechanistic studies of platelet function.
Objectives:
Primary Objective: 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.
Endpoints:
Primary Endpoints: Establish and validate technical assays and equipment (e.g. platelet aggregation, hemostasis measurements, methylation, RNA-seq, proteomics and WGS, in vitro iPSC generation and bench compound and cellular imaging screening, etc.)
Establish normal physiologic mechanisms and platelet-related parameters in healthy participant samples and how these vary longitudinally and are influenced by variables (e.g., reproducibility, fluctuation with changing diet, exercise, weight and other risk factors or new disease onset)
955 studies on the registry are indexed under Thrombosis; 171 are open to participants now.
This study's planned enrollment of 400 is above the median of 173 across 384 observational studies indexed under Thrombosis.
Browse Thrombosis studies →National Heart, Lung, and Blood Institute (NHLBI) is the lead sponsor of 1,143 studies on the registry; 71 are open to participants now.
Of its 58 completed or terminated interventional studies of FDA-regulated products, 51 (88%) have results posted.
Counted across the registry records on this site, refreshed daily.
Healthy participants, at least 18 years of age
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
In order to be eligible to participate in this study, an individual must meet all of the following criteria:
EXCLUSION CRITERIA:
An individual who, by self-report, meets the following criteria will be excluded from participation in this study:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Healthy participants, at least 18 years of age
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.
Time frame: 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.
Time frame: 10 years
Plan to share: Yes — See DMSP
Supporting information: Study protocol, Informed consent form
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.@@@
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