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The blood panel built for distance. Iron, haematology, electrolytes, and more — tailored to the physiology of endurance sport.
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Purpose-built for runners, cyclists, swimmers, and triathletes. Covers iron status, haematological markers, electrolytes, thyroid, and vitamin D.
Endurance sports place unique and sustained demands on the blood, skeleton, and endocrine system. Iron deficiency — including the pre-anaemic stage where ferritin is low but haemoglobin is still normal — is the single most common correctable cause of performance decline in endurance athletes. Foot-strike haemolysis in runners, high sweat losses, and increased gut transit that reduces absorption all compound the problem. This panel focuses specifically on the markers most relevant to distance training: the full iron cascade (ferritin, serum iron, TIBC, transferrin saturation), haematological parameters (haemoglobin, haematocrit, MCV), electrolyte balance, thyroid function, and vitamin D status. Results are reviewed by a GMC-registered physician with commentary tailored to an endurance-sport context.
Understand what each marker measures, why it matters, and what the science says — not just a list of numbers.
This panel is designed for adults who want a comprehensive, evidence-based picture of their metabolic health — not a GP referral panel.
Marathon, half-marathon, and ultra-distance runners
Cyclists and triathletes competing at amateur or club level
Swimmers and open-water competitors
Athletes following high-volume training plans preparing for a target event
Anyone who has experienced unexplained performance decline during a training block
The haematological markers in this panel reflect a single point in time and are sensitive to hydration status at the time of collection; dehydration artificially raises haematocrit and haemoglobin while haemodilution (a normal adaptation to endurance training) lowers them. Serum iron fluctuates significantly within the day and with meals; overnight fasting and morning collection improve reliability. Foot-strike haemolysis in runners causes plasma haemoglobin release that may transiently affect some markers if collected immediately after a run. This panel does not assess reticulocyte count, which would be the next step in evaluating red cell production kinetics, nor does it include erythropoietin or bone marrow function assessment.
From order to physician-reviewed report in as little as three working days.
Home fingerstick or mobile phlebotomist — recommended for venous iron cascade.
48 to 72 hours after your last long run or hard session. Morning, fasted.
Pre-paid Royal Mail envelope included.
In 3 to 5 working days with physician commentary.
Three options designed to fit your schedule, location, and preference — all producing a laboratory-standard sample.
Adults 18+ in mainland UK. Not suitable if you have had a transfusion in the last 3 months.
Order anytime; kit dispatched within 24 hours Mon–Fri.
Allow 24–48 hours for sample transit on top of lab processing time.
Adults 18+ within 20 miles of a serviced city centre.
Mon–Sun, 06:00–20:00. Next-day booking typical.
Sample reaches the lab within 24 hours of collection.
Adults 16+ with photo ID. Paediatric draws by appointment at selected sites.
Mon–Fri, with Saturday hours at most metropolitan locations.
Samples processed same-day at the receiving clinic.
Every test is processed in a UKAS ISO 15189-accredited laboratory, overseen by GMC-registered physicians, and governed by UK GDPR. No overseas processing, no offshore data.
Follow these guidelines to ensure accurate, reproducible results. Most markers are sensitive to recent food, exercise, and sleep.
Can't find your answer? Our clinical support team is available Monday to Friday, 9am–5pm.
Contact supportFoot-strike haemolysis is the mechanical destruction of red blood cells that occurs when the foot repeatedly strikes a hard surface during running. The ruptured cells release haemoglobin into the plasma, which is then cleared by the kidneys and can produce dark urine. Chronically, this contributes to iron loss and may suppress haemoglobin. To avoid the acute effects on your test results, do not run on the day of collection and allow at least 24 to 48 hours after a long run before testing.
Most sports medicine guidelines suggest intervention when ferritin falls below 20 to 30 micrograms per litre in athletes, even if haemoglobin is still within the normal range. Some elite endurance athletes target ferritin above 50 micrograms per litre for peak performance. The decision should be made with a GP or sports physician, who will weigh your ferritin result against transferrin saturation, haemoglobin, symptoms, and dietary intake before recommending a supplement dose and form.
Hypothyroidism slows every metabolic process: heart rate reserve is reduced, muscle glycogen turnover is impaired, mitochondrial density declines, and body temperature regulation becomes less efficient. Even subclinical hypothyroidism (elevated TSH with normal free T4) has been associated with reduced aerobic capacity and increased perceived exertion at submaximal intensities. Because symptoms of hypothyroidism (fatigue, weight gain, cold intolerance) overlap significantly with overtraining syndrome, a thyroid panel is an important differentiation step when performance declines unexpectedly.
Mild iron deficiency without anaemia can often be managed through dietary modification and supplementation without complete training cessation. However, continuing to train hard with significantly low ferritin or established iron-deficiency anaemia delays recovery and risks further depletion. A temporary reduction in training volume, alongside nutritional intervention, is usually far more effective than simply pushing through. Seek guidance from a sports physician or your GP before making major adjustments to your programme based on test results.
Vitamin D is increasingly recognised as relevant to athletic performance beyond its traditional role in bone health. It plays a role in muscle fibre function, particularly in type II fast-twitch fibres relevant to speed work, and in immune regulation, which is important given that endurance athletes are more susceptible to upper respiratory tract infections, especially during high-volume training phases. Low vitamin D is also associated with increased stress fracture risk, which is directly relevant to high-mileage runners. Many outdoor athletes still have deficient levels in winter months.
