The Vitall kidney function test includes the most important laboratory tests for a quick and reliable assessment of kidney function. The kidney function home test kit incorporates the evaluation of urea (BUN), creatinine, and estimated glomerular filtration rate (eGFR). 

Electrolyte samples are unstable and require immediate analysis for accurate results.[4] For this reason, they’re not included in the kidney function test at home. However, you can visit patient reception for a blood draw and include these valuable results in your report. The test comprises the essential electrolytes of the human body: sodium, potassium, chloride, and bicarbonate.
 

[1] Sieck GC. Physiology in Perspective: Physiology is Everywhere. Physiology (Bethesda). 2019;34(3):167-168. doi:10.1152/physiol.00006.2019. Available from: https://doi.org/10.1152/physiol.00006.2019

[2] Wallace MA. Anatomy and physiology of the kidney. AORN J. 1998;68(5):800-824. doi:10.1016/s0001-2092(06)62377-6. Available from: https://doi.org/10.1016/s0001-2092(06)62377-6

[3] Eckardt KU. The noblesse of kidney physiology. Kidney Int. 2019;96(6):1250-1253. doi:10.1016/j.kint.2019.10.007. Available from: https://doi.org/10.1016/j.kint.2019.10.007

[4] Baruah A, Goyal P, Sinha S, Ramesh KL, Datta R. Delay in specimen processing-major source of preanalytical variation in serum electrolytes. J Clin Diagn Res. 2014;8(12):CC01-CC3. doi:10.7860/JCDR/2014/10150.5285. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4316244/

[5] Shepherd J, Hatfield S, Kilpatrick ES. Is there still a role for measuring serum urea in an age of eGFR? Evidence of its use when assessing patient hydration. Nephron Clin Pract. 2009;113(3):c203-c206. doi:10.1159/000233057. Available from: https://doi.org/10.1159/000233057

[6] Fliser D. Assessment of renal function in elderly patients. Curr Opin Nephrol Hypertens. 2008;17(6):604-608. doi:10.1097/MNH.0b013e32830f454e. Available from: https://doi.org/10.1097/mnh.0b013e32830f454e

[7] Lab Tests Online-UK. Electrolytes and Anion Gap. Accessed 5 July 2021. Available from: https://labtestsonline.org.uk/tests/electrolytes-and-anion-gap

[8] National Kidney Federation. FAQS. Accessed 5 July 2021. Available from: https://www.kidney.org.uk/Pages/FAQs/Category/faqs

[9] Samra M, Abcar AC. False estimates of elevated creatinine. Perm J. 2012;16(2):51-52. doi:10.7812/tpp/11-121. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3383162/

[10] Levey AS, Coresh J. Chronic kidney disease. Lancet. 2012;379(9811):165-180. doi:10.1016/S0140-6736(11)60178-5. Available from: https://doi.org/10.1016/s0140-6736(11)60178-5

[11] Kidney Disease: Improving Global Outcomes (KDIGO). KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2013 Jan 1;3(1). Available from: https://kdigo.org/wp-content/uploads/2017/02/KDIGO_2012_CKD_GL.pdf

[12] National Institute for Health and Care Excellence (NICE). Chronic kidney disease in adults: assessment and management. London: National Institute for Health and Care Excellence (UK); 2015 Jan. Available from: https://www.nice.org.uk/guidance/cg182

[13] Hounkpatin HO, Harris S, Fraser SDS, et al. Prevalence of chronic kidney disease in adults in England: comparison of nationally representative cross-sectional surveys from 2003 to 2016. BMJ Open. 2020;10(8):e038423. Published 2020 Aug 13. doi:10.1136/bmjopen-2020-038423. Available from: https://doi.org/10.1136/bmjopen-2020-038423

[14] Epstein M. Alcohol's impact on kidney function. Alcohol Health Res World. 1997;21(1):84-92. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6826793/

[15] National Health Service (NHS UK). Chronic kidney disease - Prevention. Accessed 6 July 2021. Available from: https://www.nhs.uk/conditions/kidney-disease/prevention/
 

The first step for taking care of your kidneys is avoiding the main causes of CKD, such as diabetes, obesity, and hypertension.

• If you have diabetes or hypertension, it is important to follow your treatment and assist to your medical appointments.[10]
• Early detection of CKD is essential. If you have any risk factors, you may require a kidney function test for screening purposes. The NICE guidelines recommend measurement of eGFR for patients with:[12]
  • Diabetes.
  • Hypertension or cardiovascular disease.
  • Acute kidney injury.
  • Any disease affecting the renal tract, such as recurring renal calculi or prostatic hypertrophy.
  • Systemic diseases that may affect the kidneys, such as systemic lupus erythematosus.
  • Family history of end-stage kidney disease.
  • Haematuria (blood in the urine).

The NHS also recommends:[15]

• Stop smoking.
• Avoid alcohol.
• Have a healthy diet.
• Have regular exercise (at least 150 minutes per week).
• Avoid overusing painkillers.

Ensure that you know your baseline kidney health by taking a kidney function test at home, then track your results online for measurable improvements.

The kidneys work together with the liver to remove waste and toxic substances from the body, including alcohol. Binge drinking may have the potential to cause acute kidney failure, which can be a life-threatening condition that may progress into CKD. On the other hand, drinking too much in a regular manner causes slow but severe alterations of kidney function, especially alongside smoking. This includes problems with electrolyte levels, acid-base dysregulation, dehydration.[14]

The liver is greatly affected by excessive alcohol intake too. As the liver is damaged by alcohol and becomes unable to metabolise it, the kidney is overloaded with work. This deadly combination may predispose to developing hepatorenal syndrome, a severe condition where a patient with liver disease develops kidney failure.[14]

If alcohol consumption is of concern to you, we also recommend taking a liver function home test. Analysis can be completed using the same blood as your kidney function test at home, requiring only one finger-prick blood sample.

The kidneys are very resilient organs and may withstand damage for a long period of time before showing any signs. As a result, abnormal kidney function can be asymptomatic in the early stages, the clinical findings may be non-specific and attributable to other diseases, and the first symptoms may appear when the disease is already well-established.[10]

First symptoms:

• Feeling tired most of the time.
• Swollen ankles, feet, or hands.
• Puffy eyes.
• Headaches.
• Bubbles in your urine.
• Muscle cramps.
• Excessive urge to urinate, especially at night (nocturia). 
• Itchy skin.
• Dry skin.
• Easy bruising.

Signs of worsening kidney disease:

• Hard-to-treat hypertension.
• Nausea and vomiting.
• Poor appetite and weight loss.
• Bone pain and fractures.
• Blood in your urine.
• Decreased urination.
• Shortness of breath.
• Mental problems.
• Sleeping problems.
• Chest pain.

While taking a kidney function home test can help you understand your kidney health, we always recommend discussing any symptoms with your GP.

Being in charge of the management of water and waste products from the body, the kidneys have to execute a number of tasks that are much more intricate than they seem. Not only because these duties are highly complex by themselves, but because they interact in a very crucial manner with the rest of the organs in the body.

The kidneys work to maintain adequate levels of water, electrolytes (such as sodium, potassium, chloride, bicarbonate), and pH (acid-base balance) in the ever-changing environment of the human body. All these elements are crucial for providing stable and resourceful conditions for the cells so they can function and develop properly.[1][2]

The kidneys participate, sometimes alongside the liver, in the elimination of external as well as internal toxic waste products; they are also in charge of promoting the production of red blood cells through the synthesis of a hormone, erythropoietin.[3].

The group of functionally active kidney cells is called a ‘nephron’, composed of a filter (glomerulus) and a tube (tubule). Renal function depends on the approximately 1.2 million nephrons that each kidney carries,[2] which can be impaired by nephron loss (such as injury or kidney donation).[1]

The kidneys are also very dynamic and resilient: after nephron loss, the remaining nephrons show increased filtration and growth to make up for the deficit. However, when this surpasses the organ’s capabilities, kidney disease ensues.[1]

Given the critical importance of kidney health, taking a blood test for kidney function is a very commonly requested test.

A kidney function blood test gives us an insight into how well the kidneys are working by including the main biomarkers filtered and regulated by the nephrons: urea, creatinine, and electrolytes.

Urea: this biomarker is a waste product from protein metabolism that is filtered by the kidneys and mostly eliminated through the urine, making it useful for screening renal health. It also provides information on hydration status.[5]

Creatinine: kidney function assessment is heavily based on creatinine levels. Its concentration is determined by the production (muscle metabolism) and elimination (kidney function) rates, serving as a relatively stable and easy-to-measure biomarker. Conveniently, as it is filtered out by the kidneys, creatinine’s clearance rate can be used to estimate the glomerular filtration rate (eGFR).[6]

eGFR: this value represents how well the kidneys are filtering blood and, thus, gives us critical information on kidney health and function. Most frequently, it is calculated with the help of creatinine levels and other variables, such as sex, age, and race. Glomerular filtration can be measured with even higher accuracy, but this requires costly, cumbersome, and invasive methods (such as intravenous injection of inulin, radioactive substances, or radio-contrast agents).[6]

Electrolytes: cells require a strict electrolyte balance to work. Sodium, potassium, chloride, and bicarbonate are vital electrolytes for the human body and their regulation is tightly linked to kidney health. They are in charge of maintaining water and acid-base balance, as well as promoting the transportation of nutrients, elimination of cellular waste products, and even cardiac muscle contraction. Other important electrolytes include calcium, magnesium, and phosphate; however, they are only ordered when a problem is suspected.[7]

Note, as detailed above electolytes are not included in a kidney test at home, these require a visit to the Patient Reception for immediate analysis. You can select this at checkout.

If your blood test for kidney function shows abnormal results it is important to understand what this may mean for your health. Abnormal kidney function means that the nephrons are unable to meet the body’s demands:

• The kidneys are unable to filter the blood as usual. This may result in the accumulation of waste products, like urea or certain drugs, which may be toxic for the body.[2]
• The nephrons will have to work harder to maintain a filtration rate, which may result in damage to kidney cells after a long time. This creates a loop where the cells keep hurting themselves while trying to reach normal kidney function.[1]
• The kidney may have problems producing erythropoietin, resulting in anaemia. If this is of concern you can take an anaemia test here.[8]
• While hypertension may lead to kidney disease, it also works the other way. If the kidneys fail to remove excess water and keep the electrolytes balanced, arterial blood pressure may rise. This, accompanied by hardening (atherosclerosis) or narrowing (stenosis) of the renal arteries, increases the risk of heart attack, stroke, and kidney failure.[8]
• Loss of calcium and decreased vitamin D activation, which occurs in the kidneys, may result in bone problems, such as a higher risk of fractures. A bone health test may also be useful.[8]
• If renal function is critically impaired, as evidenced by very low eGFR, the kidneys may require external help. Dialysis is a procedure that removes waste products and excess water outside the body, working as a healthy kidney would.[8]

Having abnormal results in a kidney function test is not the same as having kidney disease. These tests offer insight into kidney function; however, they may be altered by other factors. For example, creatinine may be higher than normal due to intense exercise, high muscle mass (bodybuilders), use of certain drugs (trimethoprim, ranitidine), etc.[9]

Each case must be studied individually for proper diagnosis. Given the importance of kidney health, you should review abnormal kidney function test results with your GP.

CKD is a long-term condition that compromises kidney performance. The term ‘CKD’ is very broad and includes multiple conditions that are characterised by structural or functional alteration of the kidneys. This means that the progression rate and severity of CKD are directly linked to the particular disorder causing it.[10]

According to KDIGO[11] and NICE[12] guidelines, the diagnosis of CKD consists of:

1. Evidence of kidney damage, such as albuminuria (albumin in the urine), structural alterations (detected by biopsy, imaging, or other methods), electrolyte disorders caused by kidney alterations, etc.
2. Decreased GFR (below 60 ml/min/1.73 m2), with or without evidence of kidney damage.
3. These alterations must be present for more than 3 months; therefore, GFR has to be measured on two or more occasions separated by at least 90 days.

Reports from England reveal that CKD is a common condition and can affect anyone, especially women and the elderly.[13] The most common risk factors of CKD include diabetes, hypertension, old age, obesity, and cardiovascular disease.

Despite being a widely known complication of diabetes and hypertension, the exact cause of CKD is difficult to find. CKD progression leads to kidney failure (end-stage kidney disease), requiring dialysis; it also represents a serious risk factor for developing cardiovascular disease and suffering a premature death.[10]

Identifying concerns early with a kidney function home test and appropriate treatment can help prevent the development of CKD.