What is an Apolipoprotein E Genotype Test?

The Apolipoprotein E (ApoE) Genotype Test determines which variant of the ApoE gene you carry. This gene provides instructions for producing Apolipoprotein E, a protein essential for transporting cholesterol and other fats through the bloodstream.

There are three main variants (alleles) of the ApoE gene: E2, E3, and E4. Everyone inherits two copies, one from each parent, resulting in one of six possible genotypes (E2/E2, E2/E3, E2/E4, E3/E3, E3/E4, or E4/E4).

Certain ApoE variants, particularly E4, are associated with an increased risk of developing high cholesterol, atherosclerosis, and late-onset Alzheimer’s disease. The E2 variant, conversely, may offer protective effects against cardiovascular disease but is linked to a rare lipid disorder called Type III hyperlipoproteinaemia.

At London Blood Tests, genetic testing is performed using polymerase chain reaction (PCR)-based genotyping, ensuring high precision and reliability.

Benefits of the Apolipoprotein E Genotype Test

·      Personalised cardiovascular risk insight
ApoE variants (E2, E3, E4) influence LDL clearance and triglyceride handling. Knowing your genotype clarifies why lipids are high or resistant to change and helps prioritise diet, exercise, and pharmacotherapy with greater precision than a standard lipid panel alone.

·      Actionable guidance for Alzheimer’s risk
The E4 allele is associated with increased late-onset Alzheimer’s risk. Results empower earlier lifestyle interventions (sleep optimisation, exercise, vascular risk control, cognitive training) and inform how aggressively to manage mid-life risk factors that impact brain health.

·      Therapy tailoring & statin response
ApoE can modulate response to statins, fibrates, and dietary fat patterns. Genotype information supports selecting the most suitable lipid-lowering strategy, anticipating side-effects, and setting realistic targets for LDL-C, non-HDL-C, and ApoB.

·      Dietary strategy that fits your biology
E4 carriers may respond better to lower saturated fat intake and a Mediterranean-style pattern, whereas E2 can be more sensitive to high carbs/triglyceride loads. Genotype-informed nutrition reduces trial-and-error and accelerates improvements in the lipid profile.

·      Family risk clarification
Because ApoE is inherited, your result can contextualise family histories of premature CVD or dementia and guide which relatives might benefit from screening, earlier lipid testing, or proactive prevention.

·      Clarity in complex dyslipidaemia
The E2/E2 genotype is linked to Type III hyperlipoproteinaemia in the right clinical context. Identifying this rare pattern can explain refractory triglycerides and guide specialist referral and targeted therapy.

·      Long-term prevention roadmap
Genotype is stable for life. A one-time test provides a durable foundation for monitoring frequency, target levels (e.g., ApoB/LDL-C), supplement choices (e.g., omega-3), and intensity of lifestyle measures across decades.

Why Do I Need an Apolipoprotein E Genotype Test?

You may need this test if you have:

• A family history of Alzheimer’s disease or early-onset dementia
• High cholesterol or triglyceride levels that are difficult to manage
• A family history of heart disease, atherosclerosis, or stroke
• Poor response to statins or other cholesterol medications
• Personal interest in genetic health risk assessment

Common symptoms or indicators prompting testing include:

• Repeatedly elevated cholesterol or LDL despite diet/exercise
• Premature cardiovascular disease (under age 55 in men, 65 in women)
• Strong family predisposition to dementia or cognitive decline

This test provides valuable insight for preventive health management and supports clinicians in tailoring nutritional, lifestyle, and pharmacological interventions.

Step-by-Step: How the Test Works

In-Clinic Testing at London Blood Tests

1. Book & pre-visit essentials
• Schedule online or by phone (no referral needed).
• You’ll receive a brief digital questionnaire (lipid history, meds, family history) to support interpretation.
2. Arrival, consent & ID check
• Photo ID verified; consent taken for genetic testing and secure data handling.
• Optional: quick discussion to choose venous blood vs buccal (cheek swab) collection.
3. Sample collection
• Venous blood draw (preferred for DNA yield) or buccal swab if you prefer a non-blood option.
• Collection takes ~5–10 minutes; samples are barcoded for chain-of-custody.
4. Laboratory processing (UKAS-accredited genetics lab)
• DNA is extracted and genotyped using PCR-based assays for the canonical ApoE SNPs (rs429358 and rs7412) that define E2/E3/E4.
• Rigid internal controls and duplicate calls ensure >99.9% analytical accuracy.
5. Quality control & verification
• Any ambiguous calls are re-run; discordant results trigger secondary confirmation before release.
6. Results & secure delivery
• Turnaround is typically ~10 business days from lab receipt.
• You’ll get a digital report stating your genotype (e.g., E3/E4) with plain-English interpretation and practical guidance notes.
7. Optional GP consultation
• Book a review to translate genotype into an action plan: lipid targets, diet strategy, medication considerations, and monitoring cadence.
• If indicated, we can coordinate adjunct tests (e.g., ApoB, Lipoprotein(a), hs-CRP, LDL-C) to refine risk.

At-Home Blood Draw (Home/Hotel Phlebotomy, UK-Wide)

1. Schedule your visit
• Choose a convenient slot for a phlebotomist to visit your home or hotel (evenings/weekends often available in major areas).
2. Professional visit & setup
• A certified phlebotomist arrives with sterile, single-use equipment and verifies ID/consent for genetic testing.
3. Sample collection
• Venous blood is drawn on-site (preferred). If pre-arranged, a buccal swab can be taken as an alternative.
• Tubes/swabs are barcoded and documented for secure chain-of-custody.
4. Courier to laboratory
• Your sample is packaged in temperature-appropriate containers and couriered the same day to our UKAS-accredited genetics lab.
5. DNA extraction & genotyping
• The lab performs PCR genotyping of rs429358/rs7412 to determine ApoE E2/E3/E4 status, with full QC.
6. Results & follow-up
• Receive your secure digital report in ~10 business days.
• Optional GP consult (phone/video) to interpret results, set lipid/brain-health targets, and plan monitoring or therapy.

Your Apolipoprotein E Genotype Results – Explained

Your result will identify which ApoE alleles you carry (E2, E3, E4).

Possible Genotypes and Their Interpretation:

• E2/E2: Rare; may lead to Type III hyperlipoproteinaemia but generally low Alzheimer’s risk.
• E2/E3: Slightly lower cholesterol levels and modest protection against heart disease.
• E3/E3: Most common and considered neutral or “normal” genotype.
• E3/E4: Slightly higher cholesterol levels and mildly increased Alzheimer’s risk.
• E2/E4: Mixed risk — protective for heart disease (E2) but modestly elevated Alzheimer’s risk (E4).
• E4/E4: Highest genetic risk for Alzheimer’s disease and elevated LDL cholesterol.

Key Notes:

• Carrying an E4 allele increases Alzheimer’s risk but does not guarantee disease development.
• Lifestyle factors — such as exercise, diet, cognitive activity, and vascular health — significantly modify risk.
• A GP or genetic counsellor can help interpret your result and guide next steps.