Clonal Hematopoiesis (CHIP): The Complete Guide
What clonal hematopoiesis is, the 15 genes a CardioHemeRISK test reads, how the score works, and how to act on results.
Medically reviewed by Rhonda Collins, FNP-C | Mito Health on August 27, 2026.
Clonal hematopoiesis (CH) is an age-associated process in which a single blood stem cell acquires a mutation that gives it a growth advantage, so it expands into a population of blood cells carrying that same mutation. It is measurable with a specialized DNA sequencing blood test, and it has strong observed associations with heart attack, stroke, and blood cancers. Those associations come from observational studies, so association is not causation, and CH is not a guideline-endorsed population screening test. It is not a diagnosis. A clinician interprets any result in the full context of your history.
This guide explains what CH is, the 15 genes the CardioHemeRISK test reads, what variant allele frequency means, how the CardioHemeRISK score maps to categories and re-test intervals, the test’s analytical performance, who may benefit, how to prepare, and how to act on results.
What is clonal hematopoiesis?
Every day your bone marrow produces billions of blood cells from a pool of hematopoietic (blood) stem cells. Over time, one of those stem cells can pick up a somatic mutation, meaning a mutation acquired during life rather than inherited. If that mutation gives the cell a competitive edge, its descendants slowly come to make up a larger and larger share of your blood. That expanded, genetically identical population is a clone, and its presence is clonal hematopoiesis.
CH is an inflammatory process. It becomes more common with each decade of life past 40, and it is independent of ancestry (Jaiswal S and Ebert BL, Science 2019;366:eaan4673). The same clones linked to blood cancers are also linked to cardiovascular risk, which is why one blood test can speak to both. Detectable somatic mutations are rare before age 40 and rise with age (Jaiswal S et al., NEJM 2014;371:2488).
What CardioHemeRISK is. CardioHemeRISK is a prescription-only blood-based next-generation sequencing test. It detects aging- and lifestyle-related CH mutations across 15 genes and returns a CardioHemeRISK score that estimates risk of heart attack, stroke, and leukemia. The score is based on the CH variant with the highest detected variant allele frequency plus the risk conferred by the specific variant or variants found.
You can start with CardioHemeRISK, or take the Mito quiz to frame your broader risk picture first.
Which 15 genes does the test read?
CardioHemeRISK sequences 15 genes associated with clonal hematopoiesis:
ASXL1, CALR, DNMT3A, FLT3, IDH1, IDH2, JAK2, MPL, PPM1D, RUNX1, SF3B1, SRSF2, TET2, TP53, and U2AF1.
Some of these are flagged as myeloid-significant when mutated, including JAK2 V617F, CALR, MPL, IDH1 and IDH2, and FLT3. The test does not include every gene associated with cardiovascular or blood-cancer risk, so a result with no detectable CH does not rule out risk from other sources.
What does variant allele frequency (VAF) mean?
Variant allele frequency (VAF) is the fraction of DNA copies at a given position that carry the mutation. It is a rough proxy for how large a clone has grown: a higher VAF generally means a larger share of your blood cells carry the variant. The disease associations reported for CH are strongest at higher clone sizes, and the studies below used a threshold of VAF greater than 10%. CardioHemeRISK builds its score from the CH variant with the highest detected VAF together with the risk conferred by the specific variants present.
What do the risk associations look like?
CH has been associated with higher rates of several serious outcomes. Read these carefully: they come from different studies, different populations, and different study designs, so they are not interchangeable. Hazard ratios (HR) come from cohorts that followed people over time. The odds ratio (OR) comes from case-control studies, which compare people who already had an event against those who did not. Association does not prove causation:
Outcome | Who the estimate describes | Association | 95% CI |
|---|---|---|---|
Coronary heart disease | CH carriers | ~1.9x (HR 1.9) | 1.4 to 2.7 |
Early-onset heart attack (age 50 or under) | CH carriers | ~4x (OR 4.0) | 2.4 to 6.7 |
Coronary heart disease | Carriers of the JAK2 V617F mutation only | ~12x (HR 12.0) | 3.8 to 38.4 |
Ischemic stroke | CH carriers | ~2.6x (HR 2.6) | 1.4 to 4.8 |
Hematologic cancer (leukemia) | CH carriers | ~12.9x (HR 12.9) | 5.8 to 28.7 |
Hematologic cancer (leukemia) | CH carriers with VAF 10% or higher | ~49x (HR 49) | 21 to 120 |
Sources: coronary heart disease, early-onset heart attack, and the JAK2-specific estimate from Jaiswal S et al., NEJM 2017;377:111. Ischemic stroke and the VAF 10% or higher leukemia estimate from Jaiswal S et al., NEJM 2014;371:2488. Hematologic cancer in CH carriers from Genovese G et al., NEJM 2014;371:2477. The JAK2 V617F estimate covers a small subset of CH carriers, so it is not the risk for CH generally.
An important nuance: the association is not uniform across all ages. In individuals aged 80 and older, the presence of CH did not associate with higher mortality (van Zeventer IA et al., Blood Advances 2021;5(8):2115). Separately, some exploratory studies have shown that anti-inflammatory drugs can reduce CH levels, but that is an early research finding only and is not a treatment claim.
How does the CardioHemeRISK score work?
Your CardioHemeRISK score maps to a CH category by the highest detected VAF, and each category comes with a recommended re-test interval. A score of 0.0 means CH was not detected.
Score | Category | Typical re-test interval |
|---|---|---|
0.0 | Not Detected | Per your clinician |
>0.0 to <0.5 | Trace | Repeat in 3 years |
0.5 to <2.0 | Slightly Elevated | Repeat in 3 years |
2.0 to <10.0 | Moderately Elevated | Repeat annually |
≥10.0 | Highly Elevated | Repeat annually |
CardioHemeRISK score bands, categories, and re-test intervals, per the CardioHemeRISK report framework. This chart is illustrative. Your own report gives the specific genes found and your recommended interval.
When myeloid-significant mutations are detected alongside a Slightly Elevated or Moderately Elevated score, a clinician may choose to re-evaluate at 1 to 3 year intervals. The specifics always come from your individual report, not from the illustrative bands above.
How accurate is the test?
CardioHemeRISK is designed to detect very small clones. Its analytical performance, measured against commercial genomic DNA standards, is:
- Limit of detection: 0.05% VAF for both single-nucleotide variants (SNVs) and insertions or deletions (indels).
- SNVs: specificity >99%, sensitivity >92%.
- Indels: specificity >99%, sensitivity >91%.
The test is run in a CLIA/CAP-accredited laboratory (Lucence Health Inc.). It is a laboratory-developed test, not FDA cleared, and it is not diagnostic.
Who may benefit from CH testing?
CH is more common, and testing may be more informative, in:
- healthy adults aged 40 to 80, since prevalence rises with each decade past 40;
- cancer survivors treated with chemotherapy or radiation, treatments that can select for CH clones; and
- people with atherosclerotic disease (such as coronary artery disease or ischemic stroke) or its risk factors, including family history, hypertension, and high cholesterol (Jakubek YA et al., Translational Research 2023;255:171).
The “silent” nature of these events is part of why some clinicians take an interest in CH: about 1 in 4 heart-attack patients have no known risk factors (Paul GK et al., Global Heart 2023;18(1)), about 1 in 5 stroke patients have no known risk factors (Beharry J et al., European Stroke Journal 2025), and about 1 in 3 leukemia cases are first diagnosed in the emergency room (Leukaemia UK and Leukaemia Care, 2022).
As an expert view rather than a population mandate, in his book Super Agers, Dr. Eric Topol has said he believes clonal hematopoiesis should be routinely assessed in older adults as part of a comprehensive risk assessment. That is one clinician’s position within an individualized approach, not a screening guideline.
How do you prepare, and who cannot test?
Preparation is light. Avoid a heavy meal in the 4 hours before your draw. No overnight fast is required. The sample is collected into 2 x 10 mL Streck tubes, which stabilize cell-free DNA.
The test is not recommended for anyone who has ever had a bone-marrow transplant, or who has had a blood transfusion within the past 2 weeks, because donor blood cells or DNA would confound the result. CardioHemeRISK also does not assess inherited or germline genetic risk, and it does not include every gene associated with these outcomes, so some at-risk individuals will have no detectable CH.
For the full ordering path, cost, and turnaround, see the companion article on how to get tested for CHIP and what it costs.
How do you act on your results?
A CardioHemeRISK score is a risk signal, not a diagnosis, so the goal is to fold it into a plan with your clinician:
- Discuss the result with your doctor. The category, the specific genes, and your VAF together shape what, if anything, to do next.
- Consider follow-up. Depending on the findings, a clinician may suggest cardiology and/or hematology follow-up. Myeloid-significant mutations can prompt closer hematologic monitoring.
- Manage cardiovascular risk factors. Because CH is associated with cardiovascular events, attention to blood pressure, cholesterol, and other modifiable risk factors is a reasonable focus.
- Remember the exploratory findings are exploratory. Any anti-inflammatory angle is early research, not a treatment recommendation.
Ordering through Mito is designed to make that plan easier. A telehealth partner reviews and orders the test when appropriate, a mobile phlebotomist draws your blood at home or work, your result sits alongside the rest of your Mito bloodwork rather than in a silo, and you can ask follow-up questions through Mito Concierge or book a 1:1 consultation to talk it through.
Clonal hematopoiesis questions
Is clonal hematopoiesis a cancer? No. CH is the presence of an expanded clone of blood cells carrying a mutation. It is associated with a higher rate of blood cancers, but most people with CH do not develop one. It is a risk signal, not a diagnosis.
Can a standard blood test find CH? No. A complete blood count measures cell counts, not the low-level DNA mutations that define CH. Detecting CH requires targeted DNA sequencing.
What is a normal CardioHemeRISK score? A score of 0.0 means CH was not detected. Higher scores map to Trace, Slightly Elevated, Moderately Elevated, and Highly Elevated categories. Your report gives your specific interpretation and re-test interval.
Does CH mean I will have a heart attack? No. The reported associations are strong but observational, so they do not prove that CH causes these events in any individual. Your clinician weighs the result against the rest of your risk picture.
Should everyone get tested? CH is not a guideline-endorsed population screening test. Testing is a decision to make with a clinician, and it may be more informative for the groups described above.
Related reading
- How to Get Tested for CHIP: Cost and Steps
- What Is Clonal Hematopoiesis (CHIP)?
- Does a Standard Blood Test Detect CHIP? CBC vs. CH Sequencing
- Clonal Hematopoiesis and Heart Disease
Medical disclaimer
This guide is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Clonal hematopoiesis testing is not a guideline-endorsed population screening test, and its disease associations come from observational research, so association does not prove causation. CardioHemeRISK is a laboratory-developed test, not FDA cleared, and it is not diagnostic. A qualified clinician should order the test when appropriate and interpret any result in the context of your symptoms, history, and other testing.
