Training Essentials Blood Test

A liver enzyme that leaks into the blood when liver cells are stressed. Mildly raised ALT is common after heavy training, recent alcohol, certain medications, or fatty changes in the liver. Persistently high ALT is worth discussing with a GP.

An enzyme that leaks into your blood when liver cells are stressed or damaged. Often looked at alongside ALT to give a clearer picture of liver health. Heavy exercise can also raise it temporarily.

A waste product your muscles produce that's filtered out by your kidneys. Levels can shift with muscle mass, hydration status and protein intake, so very muscular people often sit slightly higher than the population average.

An estimate of how efficiently your kidneys filter blood, calculated from your creatinine. Higher is generally better. It's the single most-used indicator of overall kidney functio n.

The total amount of cholesterol circulating in your blood, including both protective (HDL) and less-protective (LDL) types. On its own it tells you very little, which is why we always read it alongside HDL, LDL and the ratio below.

The cholesterol that picks up excess from your arteries and returns it to your liver. Higher HDL is generally protective. It's influenced by exercise, alcohol intake, and the types of fat in your diet.

The cholesterol most associated with build-up in artery walls when it sits high for years. Diet (especially saturated fat), genetics, body composition and activity level all influence LDL (Low Density Lipoprotein).

A form of fat your body uses for energy. Levels are heavily influenced by recent meals (which is why we ask you to fast), alcohol, carbohydrate intake and overall body composition.

A marker your liver releases when there's inflammation anywhere in the body. High CRP can reflect short-term inflammation (a recent illness, intense training, an injury) or longer-term, low-grade inflammation linked to lifestyle, sleep and stress.

Your average blood sugar level over the past 8-12 weeks, expressed as a percentage. Often called your "glucose memory" because, unlike a single glucose reading, it can't be gamed by a recent meal or fast.

The same measurement in mmol/mol, the unit the NHS and UK clinicians use. We show both so you can compare to NHS or older test results easily.

Your body's stored iron, the long-term iron savings account. Low ferritin is the earliest sign of iron deficiency, often appearing before iron itself drops or anaemia develops. Common in women with heavy periods, athletes, and people on plant-based diets.

The vitamin your body makes from sunlight and gets from food. Affects bones, muscles, mood, and immune function. UK adults often run low in winter months.

The principal male sex hormone, also important in women at lower levels. Influences muscle mass, libido, mood, energy and bone density. Levels naturally peak in the morning, which is why we ask for a morning sample.

The pituitary signal that tells your thyroid how hard to work. Counter-intuitively, high TSH usually means your thyroid is under-active (the brain is shouting at it), and low TSH often means it's over-active.