Understanding Your Blood Tests: What the Numbers Mean for Your Longevity

Your blood carries a record of everything you've done and everything you haven't. Learning to read it is one of the highest-leverage investments you can make in your health.

Blood tests are unusual in medicine: they're one of the few tools that can reveal what's happening inside your body before you feel anything at all. Cardiovascular disease, insulin resistance, thyroid dysfunction, liver stress — all of these develop quietly, over years, with no symptoms. By the time most people notice something is wrong, the process has been underway for a decade.

This is why regular blood testing matters for longevity. Not to diagnose disease — your doctor does that — but to catch the slow drifts before they become problems.

The 17 Markers We Track

The biomarkers in this app are selected for one reason: they have the strongest evidence linking them to long-term health outcomes — cardiovascular disease, metabolic function, organ health, and all-cause mortality. They fall into six groups.

Cardiovascular Risk: LDL cholesterol, ApoB, Lp(a), HDL cholesterol, total cholesterol, and triglycerides. Together these paint a picture of how much atherogenic particle traffic is circulating in your blood — the primary driver of arterial plaque over time.

Metabolic Health: Fasting glucose, HbA1c, and fasting insulin. These three tell you how well your body is managing blood sugar and, critically, whether insulin resistance is developing before blood sugar itself becomes abnormal.

Inflammation: hsCRP (high-sensitivity C-reactive protein). A single marker, but one of the most powerful. Chronic low-grade inflammation is a root driver of cardiovascular disease, cancer, and accelerated ageing.

Liver Function: ALT and AST. Liver enzymes that signal how hard your liver is working — and whether fat accumulation or metabolic stress is beginning to take a toll.

Kidney Function: eGFR and creatinine. Your kidneys filter your blood. Declining filtration rate is both a sign of kidney disease and an independent predictor of cardiovascular risk.

Hormones & Micronutrients: TSH (thyroid function), Vitamin D, and ferritin (iron stores). Three markers that affect energy, immunity, bone health, cognition, and metabolic rate in ways that are easy to address once you know where you stand.

What "Tested" Means — And What It Doesn't

A blood test is a snapshot. Your LDL at 9am on a Tuesday after a good night's sleep and a moderate few days of eating is not identical to your LDL after a stressful week and a weekend of indulgence. Individual results can vary. Trends over multiple tests are the real signal.

This is why the app stores your history and shows you trends rather than fixating on a single number. A rising HbA1c over three years is far more informative than one reading in isolation. A ferritin that moves from 80 to 130 to 220 over two years is telling you something important, regardless of where any single value sits relative to the reference range.

Getting Tested

Most of the 17 markers can be obtained from a standard annual health check or private GP panel. A handful — fasting insulin, ApoB — are not routinely tested in standard NHS or US primary care panels, but are increasingly available through private testing services (Randox, Medichecks, Quest Diagnostics, LabCorp and others, depending on your country).

Fasting for 10–12 hours before the test is required for accurate triglyceride, fasting glucose, and fasting insulin results. All other markers can be tested without fasting, though most labs prefer a morning fasted sample.

For a full guide to accessing blood tests in your country, see: How to Get the Right Blood Tests: A Guide for the US, UK, Canada, Australia, and Europe.

The 100 Great Years perspective

Blood testing is one of the most underused tools in preventive health. Clinicians use it to catch disease; 100 Great Years uses it to spot the slow drifts that precede disease by decades. The gap between a result that looks fine on a standard lab printout and a result that reflects genuine longevity optimisation is real, measurable, and — for most markers — actionable. Understanding what your blood is telling you is not a medical exercise. It is a strategic one: the earlier you have this picture, the more decades you have to change the trajectory.

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This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before making decisions about your health.