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Glossary – Medical terms put simply

Lost in medical terminology? We explain the most important medical terms for you to know and be fluent in kidney language.


The presence of albumin (a blood protein) in the urine is called albuminuria. Normally, albumin should not be found in the urine since it is too large a protein to pass the kidney filters. However, if the kidney filter function is impaired, albumin can pass from blood to urine, which is called albuminuria.

The diagnosis of albuminuria is done with a urine test that measures the concentration of albumin in the urine. It is important to diagnose albuminuria early as it may be an indicator of kidney disease at an early stage. Treating the possible underlying disease or kidney issues can contribute to slowing down or stopping the progression of albuminuria. Patients with diabetes, hypertension, excess weight, or metabolic syndrome should be routinely tested for albumin in the urine to detect possible kidney disease early on. Timely interventions can slow down its progression, or even stop it completely.

Type 1 and 2 Diabetes

Type 1 diabetes is caused by an auto immune response of the body. The insulin producing organ, the pancreas, is attacked and destroyed by the body’s own immune cells. Consequently, the body is not capable of producing insulin anymore. Type 1 diabetes usually occurs in childhood or adolescence and requires insulin therapy as insulin is not produced in the body anymore.

Type 2 diabetes occurs if the body loses the ability to use its insulin effectively or to produce sufficient amounts of it. It is usually diagnosed in middle age or elderly people, but more and more frequently also in younger people. Therapy for type 2 diabetes usually comprises dietary restrictions, physical activity, and medication. Insulin therapy may be required in later stages of the disease. A healthy lifestyle and losing excess body weight can attenuate or slow down type 2 diabetes.


eGFR, short for estimated glomerular filtration rate, is a measure for kidney function. This value indicates the kidneys’ capability of removing metabolic waste products from the blood. The measuring unit for eGFR is millilitre per minute per 1.73 square meters of body surface.

eGFR is based on a blood test that measures creatinine in the blood. Creatinine is a waste product of muscle metabolism which is removed from the blood by the kidneys and excreted via the urine. If kidney function declines, the blood creatinine concentration rises.

eGFR is calculated based on the blood creatinine value and factors like age, gender and weight. There are different formulas for calculating eGFR to be used by doctors and laboratories. For the time being, the CKD-EPI formula is considered to be the most accurate.

The normal eGFR value may vary depending on age, gender, and physical shape. A value of 90 or higher is considered normal. A value below 60 can point to impaired kidney function and requires further tests to be ordered by a doctor.



Creatinine is a waste product of muscle metabolism that is continuously produced by the muscles. It passes on to the blood and is removed from the body by the kidneys. An elevated blood creatinine value may point to impaired kidney function as the kidneys may be losing the capacity to fully remove creatinine from the body.

For measuring blood creatinine, a blood sample is taken and analysed in a laboratory. The creatinine value is affected by different factors like age, gender, muscle mass, diet, and medication.

Creatinine clearance

For calculating creatinine clearance, both the creatinine in the blood and in the urine are measured. Creatinine clearance is then calculated by dividing the amount of creatinine that is excreted per minute by the blood creatinine concentration. A 24-hour urine collection is usually required for the determination of creatinine clearance.

Creatinine clearance is the more demanding method for estimation of kidney function. Usually, eGFR is preferred.


Point-of-Care-Tests (POCT) are medical tests which can be performed directly at the location of medical care, near the patient and without the need of sending samples to a laboratory. These tests quickly provide a result and allow health care professionals to make instant decisions on therapies.

POCTs can be used at whatever location, e.g. doctors’ offices, clinics, emergency rooms, ambulatory care facilities, and even in home care and outdoors (e.g. in disasters). There are multiple kinds of POCTs, including tests for controlling blood sugar, creatinine, electrolytes (blood salts) pregnancy, infections, recreational drug and alcohol levels and even for diagnosing of heart attacks or strokes.

The main advantage of POCTs is the rapid provision of results, which can be key for immediate patient advice and care care. They may also be more cost effective than regular tests as they require less time and resources for sample preparation and analysis.


Retention marks the build-up of waste products and fluids in the body due to an impaired capability of the kidneys to remove them. Especially in later stages of chronic kidney disease the retention of waste products and fluids can result in swellings, fatigue, nausea, and itching. Therapies may be required to support kidney function and to reduce the build-up of waste products and fluids in the body.


The transparent part of the blood that remains after the removal of blood cells and coagulation factors. The serum contains a multitude of substances such as electrolytes, enzymes, hormones, proteins and metabolic waste products which are important for diagnosis and monitoring of different diseases, including chronic kidney disease. Since the kidneys are responsible for balancing electrolyte metabolism and removing metabolic waste products, their failure may result in elevated levels of waste products such as urea, creatinine, and uric acid in serum.

Chronic kidney disease can cause metabolic disorders that in turn may affect serum concentrations of other substances. Measuring their values in patients with chronic kidney disease helps to assess the severity level of the disease and to make plans for the appropriate therapy.


The UACR value (short for Urine Albumin Creatinine Ratio) is a medical test for diagnosis and monitoring of kidney diseases. It is a measure for the ratio of albumin to creatinine in urine.

An increased UACR value points in particular to kidney tissue damage and the leakage of blood proteins such as albumin into the urine.

The UACR test is usually performed when a person is at risk of kidney impairment, e.g. patients with diabetes or hypertension. When used as a screening test, it is helpful for identifying people with an increased risk of kidney disease.

An elevated UACR value may point to kidney disease at an early stage which has to be treated to prevent further damage.