What the panel measures
Your kidneys do two main jobs that show up in blood tests. They remove waste products, and they keep the levels of salts and acids in the blood within a narrow range. A kidney function panel checks both. Most labs include the following, though the exact list varies:
| Test | What it is | Why it matters for the kidneys |
|---|---|---|
| Urea | A waste product made in the liver when the body breaks down protein | Cleared by the kidneys. It rises when filtration falls, but also with dehydration and a high protein intake. |
| Creatinine | A waste product from muscle | The main blood marker of filtration. Used to calculate eGFR. |
| eGFR | A calculated estimate, not a separate test | The best single number for kidney filtration. Many labs print it with creatinine. |
| Sodium | The main salt in the blood | Reflects the balance of water and salt in the body. The kidneys help control it. |
| Potassium | A mineral that controls nerve and muscle signals, including the heartbeat | The kidneys remove extra potassium. Levels can rise when kidney function is reduced, or with some medicines. |
| Chloride | A salt that moves with sodium | Helps assess water balance and acid balance. |
| Bicarbonate | Sometimes called "CO2" or "total CO2" on reports | A buffer that keeps blood from becoming too acidic. Low levels can occur in kidney disease. |
Some labs add calcium, phosphate, uric acid or albumin. When kidney disease is known, a clinician may request these, along with a full blood count to check for anaemia (a low red blood cell count), which can develop in advanced kidney disease.
Why it is ordered
This is one of the most common panels in any Kenyan hospital or lab. It is requested during routine check-ups, for people with diabetes or high blood pressure, before and during treatment with medicines that affect the kidneys or salts, when someone is admitted to hospital or is vomiting, has diarrhoea or is dehydrated, and to monitor known chronic kidney disease (CKD). Potassium and sodium are also checked in people taking certain blood pressure and heart medicines.
How the sample is taken and how to prepare
Blood is drawn from a vein in the arm. Fasting is not usually needed for this panel, unless other tests on the same form require it. The advice for creatinine applies: if advised, avoid a large meal of cooked meat and heavy exercise before the test, and drink normally.
How the sample is handled matters a great deal for potassium. If the red blood cells break open in the tube, a process called haemolysis, they release potassium and the result reads falsely high. This can happen with a difficult blood draw, a long tourniquet time, repeated fist clenching, shaking the tube or a long delay before the sample reaches the lab. Labs often write "haemolysed sample" on the report when they notice it.
How results are reported
Kenyan labs usually report:
- Urea in mmol/L. Some reports, especially from the United States, show BUN (blood urea nitrogen) in mg/dL instead. BUN and urea are related but the numbers are not the same, so compare like with like.
- Sodium, potassium, chloride and bicarbonate in mmol/L.
- Creatinine in µmol/L, sometimes mg/dL. To convert µmol/L to mg/dL, divide by 88.4.
- eGFR in mL/min/1.73m², often with the G category. See eGFR explained.
Reference ranges differ between labs and equipment, and some depend on age and sex. Use the range printed on your own report. Values outside the range are usually flagged "H" or "L".
What can affect the result
- Dehydration raises urea more than creatinine, and can also raise sodium. This pattern is common after vomiting, diarrhoea or a hot day without enough fluid.
- Protein intake and bleeding. A high protein diet, bleeding in the stomach or gut, and some medicines such as steroids can raise urea. Liver disease and a low protein diet can lower it.
- Sample handling can raise potassium falsely, as described above.
- Medicines. Diuretics (water tablets) and several blood pressure medicines can change sodium and potassium. Do not stop any medicine because of a result: discuss it with the prescriber.
- Diet. Very high potassium intake matters mainly when kidney function is reduced. A clinician or dietitian can advise whether any change is needed.
What the panel cannot tell you on its own
A kidney function panel shows how the kidneys are coping at one moment. It cannot tell you the cause of a problem, and it does not look at the urine. KDIGO 2024 guidance assesses chronic kidney disease using eGFR and urine albumin together, with changes lasting more than 3 months. A normal panel can sit alongside early kidney damage that shows up only in a urine ACR. A single abnormal panel, especially during an illness, may reflect a short-term change rather than lasting disease.
Related tests
- Creatinine test and eGFR: the core filtration results.
- Urine ACR and urinalysis: the urine side of kidney testing.
- Kidney ultrasound: size and structure of the kidneys.
When to discuss your result with a clinician
Arrange a review if any value is flagged, if your eGFR is below 60 or has fallen, or if you are taking medicines that affect potassium or sodium. Your clinician may repeat the test to check whether a result was a one-off. Bring all your earlier reports, and a list of medicines, to the appointment. Our page on what happens at a kidney consultation explains how to prepare.
When to get medical help urgently
If a lab or doctor has told you that your potassium or sodium result is dangerously high or low, seek same-day care at the nearest hospital emergency department, even if you feel well. Go immediately if you also have palpitations, muscle weakness, confusion, very little or no urine, or severe breathlessness.
Common questions
What is the difference between UECs, RFTs and KFTs?
They are different names for similar blood panels. UECs stands for urea, electrolytes and creatinine. RFT means renal function test and KFT means kidney function test. The exact tests included vary by lab, so check the list printed on your report.
Does a normal kidney function test mean my kidneys are healthy?
Not always. A blood panel can be normal in early kidney disease, when the only sign is albumin in the urine. That is why a urine ACR test is also used, especially for people with diabetes or high blood pressure.
Sources
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. kdigo.org
- NICE guideline NG203: Chronic kidney disease: assessment and management. nice.org.uk
- National Institute of Diabetes and Digestive and Kidney Diseases: Kidney disease. niddk.nih.gov
This page explains what a test or condition involves. It is not a diagnosis and does not replace advice from a doctor who knows your history. Your results should be interpreted together with your symptoms, other tests and a clinical assessment. Medical disclaimer.