Marker group

Kidney Function

Plain-English guides to the kidney function markers we measure and what your results mean, written to inform the conversation with your practitioner.

Markers in this group

BicarbonateBicarbonate is your blood's natural buffer — it soaks up excess acid and stops your blood from becoming too acidic or too alkaline. Your kidneys and lungs keep it within a narrow range, and the result shows whether that balance is being kept. It is almost always read as part of a group of minerals rather than on its own.ChlorideChloride is a charged mineral that shadows sodium almost everywhere it goes, helping to keep your body's fluids balanced and your nerve signals smooth and steady. It is nearly always measured as part of a group of minerals rather than on its own, and an in-range result simply means your fluid and salt balance is ticking along as it should.CreatinineCreatinine is a waste product your muscles make that your kidneys filter out — so it is one of the main ways to check how well your kidneys are working. A result inside your report's range usually means they are clearing waste as expected. A higher level can mean they are filtering less efficiently, though muscle, a hard workout or dehydration can nudge it too.Estimated Glomerular Filtration Rate (eGFR)eGFR is an estimate of how well your kidneys are filtering, worked out from a blood test. A result of 60 or above usually suggests they are working normally. One reading below 60 is not a diagnosis on its own, it is only a flag for long-term kidney change if it stays low for more than three months, which is why your GP repeats the test to see the trend.PotassiumPotassium is a mineral that helps keep your heart beating steadily and your muscles working smoothly. Your kidneys hold it within a tight range, because both too much and too little can upset your heart rhythm. A result inside the range is reassuring; a result outside is worth a chat with your GP to find out why.SodiumSodium is a salt that helps keep your body's water and nerve signals in balance, and your kidneys hold it within a tight range. The result on your report shows whether that balance is being kept. A result inside the range is reassuring; a result outside usually points to something simple, like how much fluid you have had, that your GP can look into.UreaUrea is a waste product your body makes when it breaks down protein, and your kidneys clear it from your blood — so a urea test is one way to check how well they are filtering. It is easily swayed by everyday things like how much protein you eat and how hydrated you are, so a result outside the range is usually read alongside other kidney tests.

Reading results in this group

a little low

Lower kidney markers like creatinine are generally not a concern and can be a normal finding. Creatinine relates to muscle mass.

Possible reasons:

This can relate to hydration, diet, or medicines that affect electrolytes.

Next steps: Discuss with your GP, especially if you take diuretics or other relevant medicines.

in range

Your kidney function markers are in the expected range, indicating your kidneys are effectively filtering waste products.

Possible reasons:

Adequate hydration and stable health often support in-range results.

Next steps: No follow-up is usually needed.

a little high

Elevated kidney markers may be associated with dehydration, certain medications, or changes in kidney function. Single results are less useful than trends over time.

Kidney function changes often don't cause symptoms until more advanced stages. Early detection through blood tests allows for proactive monitoring.

Possible reasons:

This can relate to hydration, diet, muscle mass, or medicines; eGFR is interpreted with creatinine.

Next steps: Discuss with your GP. Repeat testing or urine checks may be considered.

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