Can diet or exercise change the outcome of a DNA test?

No. Lifestyle can change gene expression (epigenetics) but not the DNA sequence that most commercial tests read.

Why did my twin and I get slightly different ancestry percentages?

Small statistical differences arise because the algorithm samples a subset of DNA markers; the underlying genomes are identical.

How often are variants of uncertain significance reclassified?

Current ClinVar data show that about 8 percent of VUS entries gain a clear benign or pathogenic label within five years.

Is blood or saliva more accurate for germline testing?

Accuracy is similar if the sample meets quality thresholds, but saliva is more prone to bacterial contamination and low DNA yield.

I had a bone-marrow transplant—can I still do genetic testing?

Yes, but use a cheek swab, hair root, or skin biopsy so the lab analyzes your own cells, not donor blood cells.

Do home ancestry tests screen for serious diseases?

Most direct-to-consumer kits look at fewer than 40 disease variants and miss the majority of clinically important mutations.

What if my pharmacogenomic result conflicts with my current medication dose?

Bring the report to your prescribing physician; they may order a confirmatory test before changing treatment.

How secure is my genetic data in the Eureka app?

Data are encrypted in transit and at rest, and Eureka never shares identifiable DNA information without explicit consent.

What makes a genetic test come back positive, negative, or inconclusive?

Which core factors decide what your genetic test shows?

Every report—whether it says you carry a BRCA1 mutation or that your ancestry is 47 % Scandinavian—flows from the same chain: your DNA, the laboratory process, and the interpretation software. Disruptions anywhere in that chain change the final read-out.

Inherited DNA variants drive true positives or negativesPathogenic changes such as the BRCA1 c.68_69delAG deletion directly produce a positive result because the laboratory detects the altered sequence with high confidence.
Sample quality can override real DNA informationUp to 5 % of saliva kits arrive with bacterial contamination that masks low-frequency variants, leading to false negatives.
Sequencing technology has fixed error ratesNext-generation platforms mis-read roughly 1 in every 1,000 bases; laboratories apply coverage thresholds (usually >30×) to filter these errors.
Bioinformatics filters decide what reaches the reportVariants with population frequencies above 1 % are often labeled “benign,” so a rare but real family-specific mutation can be filtered out unless analysts manually review it.
Ambiguous variants often yield an “inconclusive” resultThe Mayo Clinic notes that when a test detects a DNA change whose health impact cannot be determined, the laboratory reports an inconclusive finding, highlighting the limits of current interpretation algorithms. (Mayo)
Choice of gene panel hinges on the clinical questionMedlinePlus Genetics explains that clinicians order broad, multi-gene or chromosome arrays when a diagnosis is unclear, but switch to focused single-gene tests when a specific disorder is suspected—so the scope of the panel directly shapes what variations can be reported. (MedlinePlus)

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When should you worry about an unexpected or uncertain result?

Most findings are straightforward, but certain patterns call for prompt follow-up. “An inconclusive result is not benign by default; it’s simply an unanswered question,” notes the team at Eureka Health.

A variant of uncertain significance (VUS) in a high-risk geneRoughly 20 % of hereditary cancer panels report a VUS; guidelines recommend re-analysis or family segregation testing rather than assuming safety.
A result that conflicts with strong family historyIf three relatives had colon cancer by age 50 yet your panel is negative, additional testing like MLH1 promoter methylation should be considered.
Low allele fraction below 20 %Mosaicism can hide disease-causing mutations; hematologic malignancy panels view variant fractions under 20 % as potential red flags.
Sample collected after bone-marrow transplantDonor cells can replace your own DNA in blood, yielding misleading results; buccal or hair‐root DNA is needed instead.
Avoid irreversible decisions based solely on a VUSJAMA describes a case where prophylactic hysterectomy and oophorectomy were performed because of a PALB2 variant of uncertain significance that was later deemed uninformative, underscoring the need to wait for reclassification before major interventions. (JAMA)
Unexpected secondary findings demand separate counselingThe Jackson Laboratory notes that secondary results—such as an unexpected hereditary cancer syndrome found during unrelated testing—often provoke anxiety and require dedicated counseling to interpret their clinical significance for the individual and family. (JAX)

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Can things you do before the test skew the findings?

Pre-analytic variables are often overlooked. “DNA is remarkably stable, but the way you handle the kit still matters,” says Sina Hartung, MMSC-BMI.

Eating or drinking within 30 minutes of a saliva collectionSucrose and bacterial DNA from food dilute human DNA, cutting usable reads by as much as 40 %.
Using mouthwash right before swabbingAlcohol-based rinses can lyse cheek cells prematurely, leading to degraded fragments that fail quality control.
Shipping delays over 7 days in high heatStudies show a 12 % drop in call rate for samples left in >30 °C conditions during transit.
Recent blood transfusionForeign donor leukocytes circulate for weeks, which can introduce mixed DNA profiles in whole-blood tests.
Bone marrow or stem-cell transplants can create chimeric DNA profilesDonor-derived white blood cells persist after a transplant, so blood or cheek-cell tests may read the donor’s genome instead of yours, prompting some labs to reject or flag these samples. (FTDNA)
Touching the swab tip introduces foreign skin cellsEven a brief finger or countertop contact can seed extra DNA, leading to mixed profiles that frequently require the lab to request a new sample. (DNATesting)

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What practical steps help you act on your genetic results?

Knowing the source of your result guides next moves. A clear action plan protects you and your relatives.

Schedule a certified genetic counseling session within two weeksCounselors translate technical language into clear risk numbers and outline surveillance or preventive surgery options.
Confirm high-impact findings with an orthogonal methodLabs routinely use Sanger sequencing for single-nucleotide variants and MLPA for copy-number changes to rule out platform error.
Share written reports with first-degree relativesSiblings or children have a 50 % chance of sharing autosomal-dominant variants; cascade testing detects carriers early.
Register uncertain variants in ClinVar update alertsSubmitting your VUS allows global labs to reclassify it; about 8 % of VUS entries are clarified every year.
Re-evaluate your plan with a genetics team every 1–2 yearsJackson Laboratory advises regular follow-up visits to update management, check new guidelines, and review any variant reclassification. (JAX)
Positive findings can drive proactive screening or preventive surgeryMayo Clinic explains that a confirmed pathogenic variant may warrant lifestyle changes, additional testing, or consideration of surgical options to lower disease risk. (Mayo)

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Which additional labs or medications relate to genetic findings?

Your DNA can trigger follow-up blood work or influence drug choices. The team at Eureka Health underscores that DNA is only part of the clinical picture.

Confirmatory tumor testing after hereditary cancer hitsIf germline BRCA1 is positive, tumor BRCA1 LOH (loss of heterozygosity) testing predicts PARP-inhibitor response.
Pharmacogenomic panels guide medication dosingCYP2C19 poor metabolizers (about 2 % of Europeans) may need alternative antiplatelet therapy instead of standard clopidogrel.
Lipid profile after an LDLR mutationBaseline LDL-C helps cardiologists decide whether to start statins immediately in familial hypercholesterolemia.
Serum ferritin for HFE C282Y homozygotesLevels above 300 µg/L warrant therapeutic phlebotomy to prevent iron overload damage.
Newborn screening for PKU enables immediate dietary therapyState-mandated heel-stick DNA and phenylalanine testing can pinpoint PAH gene variants within days of birth; prompt initiation of a low-phenylalanine formula averts the severe neurocognitive damage once seen in untreated phenylketonuria. (Mayo)

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How can Eureka’s AI doctor clarify confusing genetic results?

Eureka’s chat-based AI combines large genomic databases with up-to-date clinical guidelines. “We built the model to translate variant codes into plain-language action items within seconds,” explains Sina Hartung, MMSC-BMI.

Immediate interpretation of variant nomenclaturePaste cDNA strings like NM_007294.3(BRCA1):c.5266dupC and receive a lay summary of cancer risk and management pathways.
Risk calculators using family pedigree inputsThe AI estimates your posterior probability of carrying Lynch syndrome by integrating Amsterdam II criteria.
Automated prompts for guideline-backed follow-up testsIf you upload a VUS, the tool suggests segregation analysis or protein modeling where evidence is weak.

Why most users discussing genetics rate Eureka 4.8⁄5 stars

Genetic information is sensitive; Eureka keeps it private while offering concrete steps. According to the team at Eureka Health, over 90 % of users say the app “took my concerns seriously.”

On-demand ordering of confirmatory labsEureka can route an order for Sanger sequencing to partner labs; physicians review every request before release.
Symptom tracking linked to specific variantsIf you carry MYH7 cardiomyopathy mutations, the app graphs exercise tolerance and arrhythmia episodes over time.
Safe space for family communication templatesPre-written messages help you inform relatives about their possible carrier status without causing panic.
Free to use with optional specialist escalationBasic chat interpretations cost nothing, while paid tele-genetics consults are available for complex cases.

What makes a genetic test come back positive, negative, or inconclusive?

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Key Takeaways

Which core factors decide what your genetic test shows?

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Become your owndoctor 🩺

When should you worry about an unexpected or uncertain result?

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Can things you do before the test skew the findings?

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What practical steps help you act on your genetic results?

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Which additional labs or medications relate to genetic findings?

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How can Eureka’s AI doctor clarify confusing genetic results?

Why most users discussing genetics rate Eureka 4.8⁄5 stars

Frequently Asked Questions

Can diet or exercise change the outcome of a DNA test?

Why did my twin and I get slightly different ancestry percentages?

How often are variants of uncertain significance reclassified?

Is blood or saliva more accurate for germline testing?

I had a bone-marrow transplant—can I still do genetic testing?

Do home ancestry tests screen for serious diseases?

What if my pharmacogenomic result conflicts with my current medication dose?

How secure is my genetic data in the Eureka app?

References