Blood Testing Explained
Markers, Ranges & What They Mean.
Blood testing gives you clear, objective data on key health markers — so you can understand how your body's responding and make informed decisions.
Our Recommended Partner
Gym Markers
Clinically reviewed blood testing
Objective Data
Understand what's really going on inside your body.
Track Progress
Monitor how your markers change over time.
Make Informed Decisions
Adjust your approach based on real data.
Support Long Term Health
Identify potential imbalances early and stay on track.
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Your blood carries a wealth of information about how your body's functioning. Testing key markers gives you insight into hormonal health, organ function, metabolic health and more.
Whether you're optimising performance, tracking progress during a research protocol, or just want the full picture, blood testing gives you the objective data to work from.
A blood test report typically shows several things for each marker: the test name, your measured value, the unit it's measured in, and the laboratory's reference range for that marker — the interval most people without the condition being screened for would typically fall within. Many reports also flag results as H (high) or L (low) when they fall outside that range.
A flag isn't a diagnosis. It simply means your result sits outside the laboratory's reference interval for that test, in that population, under that method. Reference ranges are statistical boundaries, not fixed thresholds for health or disease — a small number of healthy people will naturally fall just outside them, and a result can be clinically significant even within the normal range depending on the full picture. Interpreting a flagged result properly means looking at the whole report and your own history, and discussing anything unexpected with a healthcare professional — not acting on a single number in isolation.
Reference ranges aren't universal. They vary between laboratories, and even between different assay methods used for the same marker, because each range is typically derived from testing a defined reference population using that lab's specific equipment and technique.
Several factors commonly affect what a ‘normal’ range looks like for a given test:
Because of this, the reference range printed on your own report — from the lab that actually processed your sample — takes precedence over any example range you might see elsewhere, including on this page.
The markers below are grouped by the broad area of health they relate to. Each entry explains what the marker measures and why it's commonly tested — not what a specific result means for you personally.
Researchers investigating specific hormone-related research compounds may find our Compound Library a useful reference for compound-specific research background.
Why It Matters
Blood testing shows you how your body's actually responding, so you know whether what you're doing is working.
Optimise Performance
Track key biomarkers for training, recovery and overall health.
Identify Imbalances
Spot potential issues early, before they become a problem.
Measure Progress
See how your body responds over time.
Support Long Term Health
Gain insights to help you stay on track with your goals.
Key Marker Areas
Blood tests can provide insight into a wide range of health markers, including:
Cholesterol & Lipids
Understand your cardiovascular health.
Testosterone & Hormones
Key hormones, including testosterone and oestrogen.
Vitamin D
Check levels and support overall health.
Thyroid Function
Assess markers for metabolism and energy.
Blood Sugar Control
Monitor how your body manages energy.
Liver Health
Check how well your liver is functioning.
Kidney Function
Support markers for kidney health and filtration.
General Health
A full overview: blood count, inflammation and more.
The Process
Getting your bloods checked is simple with Gym Markers.
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Choose Your Test
Select a test from their range or book a clinic appointment.
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02
Provide Your Sample
At home or in clinic with a quick, easy process.
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03
Results Reviewed
Your results are analysed by GMC-registered doctors.
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04
Get Clear Insights
Receive easy to understand results with full breakdowns.
Our Recommended Blood Testing Partner
Gym Markers
Clinically reviewed blood testing
We recommend Gym Markers for blood testing. They offer a wide range of clinically reviewed tests, designed for performance, general health and wellbeing — and doctor-reviewed results come as standard. It's a partnership, but we'd recommend them anyway.
Panels & Pricing
Well Man Premier Plus — 50 markers, the full picture — £159
Sports Fitness Profile — 40 markers, training-focused — £119
Male Hormone Profile — 10 markers — £85
Testosterone Plus — 4 markers, quick check — £59
Fertility Hormones — 5 markers — £89
Weight-Loss Management — 20 markers — £99
Prices correct at time of writing — see gymmarkers.co.uk for the current range.
H means the result is above the laboratory's reference range for that marker, and L means it's below. It's a flag relative to that specific range, not a diagnosis on its own.
There are many possible explanations, from normal biological variation to the specific factors affecting that marker (timing, fasting, hydration, medication) to something that genuinely needs following up. A single flagged result is best discussed with a healthcare professional who can see your full picture.
Yes. Different labs can use different equipment, methods and reference populations, which can produce different ranges for the same marker. Always compare your result to the range printed on your own report, not a range from a different source.
The same marker can be reported in different units depending on the lab or country — for example, testosterone in nmol/L versus ng/dL. Comparing a number to the wrong unit's range can make an entirely normal result look abnormal, or vice versa.
No. A single result is one data point. Diagnosis generally depends on a wider clinical picture, including symptoms, history, trends over time and sometimes repeat testing — which is why unexpected or concerning results should be discussed with a qualified healthcare professional rather than interpreted in isolation.
Some markers, including glucose and certain hormones, naturally fluctuate throughout the day or in response to food. Tests for these markers are often specifically timed (such as fasting glucose) so results can be compared against a reference range collected under the same conditions.
It depends on your goals, but many people test every 3-6 months to track meaningful change. Your report will usually include a recommendation.
Most panels offer both. Home kits are posted directly to you; a few of the more detailed panels require a clinic visit.
Most results are available within a day of the lab receiving your sample, though this varies by panel and provider.
Yes — every panel is checked by a GMC-registered doctor before your report is released.
Your report will flag it and explain what it means. For anything that needs following up, speak to your GP.
Start with what you're trying to find out — a general check, a hormone panel, or something training- or weight-focused — and pick the panel built for that.
Your reviewing doctor's notes come with your results, and you're always free to take them to your own GP.
This page and Gym Markers' testing are general health information only — not guidance on using any Reliable Research Labs product. Speak to a qualified GP about anything specific to your situation.
This page is general health information, not medical advice. It does not provide guidance on using any Reliable Research Labs product, and nothing here should be read as dosing or safety information for human or animal use of any research compound. Reliable Research Labs products remain strictly for laboratory research purposes only and are not intended for human or veterinary use. If you have concerns about your health, speak to a qualified GP or healthcare professional. Blood testing does not guarantee any particular outcome and is not a substitute for medical advice or emergency care.
