Blood tests
Blood tests people ask about
What each test measures, why GPs check it and what can shift the number, from Hea's guide and the NHS. Ranges differ between labs — your report shows your lab's range.
Blood testHbA1cAverage blood sugar over 2–3 months, and what can shift it
Blood testFerritinYour iron stores, low iron symptoms, and what can shift ferritin
Blood testCholesterolTotal, HDL, LDL and triglycerides, and what can shift them
Blood testVitamin DStored vitamin D, why it falls in winter, and what shifts it
Blood testVitamin B12Total and active B12, deficiency symptoms, and what shifts it
Blood testTestosteroneWhy the time of day matters and what can lower it in men
Blood testeGFR (kidney function)How well the kidneys filter, read with a urine test
Blood testThyroid (TSH)TSH first, free T4 next, and why a repeat is common
Blood testLiver tests (ALT and GGT)Two liver enzymes, and what alcohol, weight and medicines do
Blood testHaemoglobinThe oxygen carrier in red cells and the main number for anaemia