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Kidney analysis: when is it needed and which methods are the most informative
The kidneys are one of the most important filtration organs in the human body. Their main function is to remove metabolic products from the blood, regulate water-salt balance, and maintain blood pressure. Kidney dysfunction can remain asymptomatic for a long time, so laboratory tests play a key role in early diagnosis.
What tests help check the condition of the kidneys?
There are several laboratory parameters that together provide an idea of kidney function. The main ones include:
1. Complete urinalysis (CUR)
The most common screening method. Allows you to assess:
Color, transparency, odor
Presence of protein, glucose, ketones
Number of erythrocytes, leukocytes, epithelial cells
Detection of salts and bacterial flora
Increased protein, blood, or leukocyte counts are common signs of glomerulonephritis, pyelonephritis, cystitis, or urolithiasis.
2. Biochemical blood test
The following indicators are important for the kidneys:
| Indicator | Norm | What does deviation mean? |
|---|---|---|
| Creatinine | 44–106 μmol/L | An increase is a sign of impaired filtration |
| Urea | 2.5–8.3 mmol/L | The increase is the result of the accumulation of toxins |
| Uric acid | 140–340 μmol/L | May indicate gout or kidney failure |
3. Glomerular filtration rate (GFR) level
Calculated by formulas (e.g. CKD-EPI or MDRD) using creatinine level, age, gender, race. It is the main criterion in the classification of chronic kidney disease.
4. Daily urine analysis
Allows you to determine:
Daily protein loss (proteinuria)
The concentrating ability of the kidneys
Excretion of calcium, sodium, potassium
This study is relevant if nephrotic syndrome, diabetes mellitus, or hypertension are suspected.
5. Microalbuminuria (MAU)
Detects the presence of small amounts of albumin in the urine, which is one of the earliest markers of kidney damage, especially in diabetes or hypertension. Important for early prevention of chronic kidney disease.
6. Cystatin C
A new biomarker of kidney function that is less dependent on muscle mass than creatinine. It is used to more accurately assess the filtration capacity of the kidneys.
When should you get kidney tests?
Kidney function testing is recommended in the following cases:
arterial hypertension
diabetes mellitus
swelling of the legs or face
change in urine color or odor
frequent urination or pain in the kidney area
use of nephrotoxic drugs (NSAIDs, chemotherapy)
hereditary predisposition to kidney disease
Preparation for tests
To get accurate results, follow these rules:
do not eat salty, smoked, or alcoholic beverages the day before
avoid physical exertion for 24 hours
do not take diuretics without a doctor's advice
for daily urine - use a sterile container and store in the refrigerator
Benefits of early diagnosis
Most kidney diseases are treatable if detected early. Laboratory tests can prevent functional changes from progressing to chronic kidney failure, which requires dialysis or transplantation.
Regular kidney function testing is not only a medical recommendation, but also an important step towards maintaining long-term health. It is especially necessary for people in risk groups, as well as for anyone who takes preventive care of their body.
