What do your genetic screening results actually mean?
By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group
Published: July 25, 2025Updated: July 25, 2025
Key Takeaways
A genetic screening result estimates your inherited risk for specific diseases, medication reactions, or carrier status. A "positive" result shows you carry a gene variant linked to higher risk; a "negative" result lowers— but never eliminates— that risk. Results guide next steps such as confirmatory testing, lifestyle changes, or specialist referral. Always interpret them with a certified genetic counselor or physician to avoid misreading probabilities.
What does a genetic screening result actually mean?
Genetic screens look for known DNA changes that raise or lower the likelihood of certain conditions. They predict risk, not certainty. A variant marked "pathogenic" means evidence links it to disease; "variant of uncertain significance" (VUS) lacks clear proof.
- Risk is expressed as probability, not destinyFor example, a BRCA1 pathogenic variant raises lifetime breast cancer risk to roughly 65%, compared with 13% in the general U.S. female population.
- Negative results narrow—not erase—possibilityMost panels test only the most studied regions; up to 10% of hereditary cancer cases involve genes not on common panels.
- Carrier status affects family planningIf both partners carry the same recessive mutation such as CFTR ΔF508, each pregnancy has a 25% chance of cystic fibrosis.
- Medication safety can hinge on single genesCYP2C19 variants triple the risk of stent thrombosis in clopidogrel users who metabolize the drug poorly.
- Expert perspective clarifies jargon"A VUS should never guide surgery or medication changes without further evidence," explains Sina Hartung, MMSC-BMI.
- False positives and negatives are possible in any screenNIH notes that a screening result estimating higher or lower risk can still be a false-positive (indicating risk when none exists) or false-negative (missing a true risk), so abnormal findings usually require follow-up diagnostic testing. (NIH)
- Genetic reports group findings as positive, negative, or uninformativeResults are typically classified as positive (pathogenic variant found), negative (no relevant variant detected), or uninformative/variant of uncertain significance; each category leads to different counseling and management steps. (NIH)
Which genetic findings should prompt immediate medical attention?
Some results carry near-term health threats that may require urgent evaluation or preventive action.
- Pathogenic BRCA1/2, TP53, or PTEN mutationsThese elevate aggressive cancer risks; guidelines recommend considering MRI screening as early as age 20.
- Long-QT syndrome gene variants like KCNQ1Sudden cardiac death risk can rise tenfold; beta-blocker therapy or defibrillator placement may be advised.
- HFE C282Y homozygosityIron overload can silently damage the liver; ferritin and transferrin saturation tests should be arranged promptly.
- APOE ε4 homozygosity discovered incidentallyCognitive decline can begin earlier; early neurology referral helps plan monitoring and trials.
- Clinician quote underscores urgency"When a result raises the odds of sudden death, same-week specialist referral is justified," note the team at Eureka Health.
- ACMG actionable 73-gene list mandates swift follow-upThe American College of Medical Genetics and Genomics directs laboratories to disclose pathogenic variants in 73 specified genes because "early diagnosis and effective intervention" are possible, so patients should be referred quickly for disease-specific screening or prophylaxis. (NIH)
- Actionable secondary variants appear in about 2–3 % of genomic testsLarge commercial testing shows that roughly 2‒3 % of individuals receive incidental findings with established medical management recommendations, underscoring the need for prompt clinical evaluation when such results are reported. (GeneDx)
How can you manage identified genetic risks in daily life?
Genetic risk usually combines with lifestyle, so behavior can still sway outcomes.
- Tailored cancer screening schedulesWomen with BRCA mutations often start annual MRI at 25, mammography at 30, doubling the detection rate of early tumors.
- Heart-protective habits matter even with LDLR mutationsIn familial hypercholesterolemia, strict diet and statin therapy can cut coronary events by 70% compared with no treatment.
- Proactive vaccinationsPeople with complement gene defects need meningococcal vaccination boosters every 3–5 years.
- Reproductive planning optionsPre-implantation genetic testing (PGT-M) allows carriers of spinal muscular atrophy to select unaffected embryos.
- Expert insight on lifestyle leverage"Even high-penetrance genes still leave room for action; smoking cessation halves lung cancer risk in EGFR carriers," says Sina Hartung, MMSC-BMI.
- Early and frequent colonoscopy curbs MUTYH-related cancer riskIndividuals with biallelic MUTYH-associated polyposis are advised to begin colonoscopy every 1–2 years at age 25–30; this is vital because their lifetime colorectal cancer risk is 70–90%, compared with about 5% in the general population. (MGH)
- Movement and low-dose aspirin reduce clot risk in Factor V Leiden carriersRoughly 5% of people of European ancestry carry the Factor V Leiden variant; taking walks on long flights and using preventive low-dose aspirin are simple steps shown to cut venous thrombosis risk, strategies highlighted by carrier and researcher Robert Green. (Harvard)
- FORCE: https://www.facingourrisk.org/info/risk-management-and-treatment/screening-and-risk-reduction/overview
- MGH: https://www.massgeneral.org/assets/mgh/pdf/cancer-center/genetics/mutyh/mutyh.pdf
- Harvard: https://news.harvard.edu/gazette/story/2025/07/riskier-to-know-or-not-to-know-youre-predisposed-to-a-disease/
Which confirmatory tests or therapies might follow a genetic screen?
A screen is only a first step. Clinicians often order targeted labs, imaging, or preventive drugs to refine risk and act early.
- Sanger sequencing validates uncertain findingsThis high-accuracy test re-analyzes the exact DNA segment, reducing false positives to below 1%.
- Serum ferritin confirms hereditary hemochromatosis burdenValues over 300 ng/mL in men trigger therapeutic phlebotomy every 1–2 weeks.
- LDL-cholesterol guides familial hypercholesterolemia therapyAn untreated LDL over 190 mg/dL may prompt PCSK9 inhibitor consideration.
- Pharmacogenomic dosing algorithmsWarfarin dose calculators incorporating VKORC1 and CYP2C9 genotypes cut hospitalizations by 30%.
- Quote on staged testing"Pairing a genetic flag with a biochemical marker sharpens decision-making," explains the team at Eureka Health.
- Sweat chloride testing confirms cystic fibrosis screening flagsNewborns with an out-of-range CF screen move to a quantitative sweat test; an elevated chloride result secures the diagnosis and permits initiation of airway clearance and pancreatic enzyme therapy. (BFT)
- Enzyme assays finalize lysosomal storage disease diagnosesDeficient lysosomal enzyme activity measured after a positive screen clinches disorders such as Pompe or MPS I, enabling presymptomatic enzyme replacement or substrate-reduction therapy before organ damage accrues. (GIM)
- MedlinePlus: https://medlineplus.gov/genetics/understanding/testing/differenttests/
- JAX: https://www.jax.org/education-and-learning/clinical-and-continuing-education/clinical-topics/genetic-testing/patient-management-after-genomic-testing
- BFT: https://www.babysfirsttest.org/newborn-screening/conditions/cystic-fibrosis-cf
- GIM: https://www.gimjournal.org/article/S1098-3600(21)04792-4/fulltext
Frequently Asked Questions
Not necessarily; most VUS never prove harmful. Your clinician may recommend periodic re-analysis or family testing.
Often, yes. For example, weight control and exercise halve diabetes onset in people with the TCF7L2 risk allele.
Re-interpretation every 12–24 months can reveal new insights without another blood draw.
Many U.S. plans cover it when a pathogenic variant or strong family history exists, but policies vary.
No. U.S. law forbids employers from accessing or using genetic information for hiring decisions.
Timing depends on the condition. For adult-onset cancers, testing usually waits until the age when screening would begin.
It complements but does not replace monitoring; levels confirm that dosing assumptions were correct.
- NIH: https://medlineplus.gov/genetics/understanding/testing/differenttests/
- NIH: https://medlineplus.gov/genetics/understanding/testing/interpretingresults/
- NHGRI: https://www.genome.gov/genetics-glossary/Genetic-Screening
- NIH: https://medlineplus.gov/genetics/understanding/testing/secondaryfindings/
- GeneDx: https://www.genedx.com/results/
- UNC: https://www.unchealthcare.org/app/files/public/26e78ecf-79fb-41c1-9c10-2b97437e8be2/pdf-system-phgs-Understanding-Test-Results-PHGS.pdf
- FORCE: https://www.facingourrisk.org/info/risk-management-and-treatment/screening-and-risk-reduction/overview
- MGH: https://www.massgeneral.org/assets/mgh/pdf/cancer-center/genetics/mutyh/mutyh.pdf
- Harvard: https://news.harvard.edu/gazette/story/2025/07/riskier-to-know-or-not-to-know-youre-predisposed-to-a-disease/
- JAX: https://www.jax.org/education-and-learning/clinical-and-continuing-education/clinical-topics/genetic-testing/patient-management-after-genomic-testing
- BFT: https://www.babysfirsttest.org/newborn-screening/conditions/cystic-fibrosis-cf
- GIM: https://www.gimjournal.org/article/S1098-3600(21)04792-4/fulltext
- FORCE: https://www.facingourrisk.org/info/hereditary-cancer-and-genetic-testing/genetic-testing/types-of-test-results