Are there different kidney tests for children or pregnant women, and how is their kidney function assessed?

There are no "completely different" kidney tests in terms of the fundamental types of examinations for children or pregnant women; blood and urine tests, such as measuring creatinine and albumin, remain the essential tools for assessing kidney efficiency [1]. However, the interpretation of these results differs significantly; standard estimated Glomerular Filtration Rate (eGFR) equations for adults, such as the CKD-EPI equation, are not used for patients under 18 years of age or during pregnancy [5]. Instead, doctors rely on a specialized interpretation methodology that accounts for physiological variables and growth, in addition to other tests determined by the physician.

Assessing Kidney Function in Children

When assessing children, the process is not limited to knowing creatinine or protein levels in the urine; rather, these results are correlated with the child’s growth stage and body size. Since standard eGFR equations are not valid for children [5], physicians may use age-specific estimation equations to assess kidney function. In addition to blood and urine tests, doctors often resort to imaging examinations such as ultrasounds to rule out congenital anomalies, which are a major cause of kidney disease in childhood [4].

Specificity of Kidney Tests During Pregnancy

Kidney tests during pregnancy require great caution in interpretation, as hormonal and physiological changes in a woman's body lead to fluctuations in blood flow and the volume of fluid passing through the kidneys. Standard eGFR equations are not valid for use during pregnancy [5]. Instead, the urine albumin test (or albumin-to-creatinine ratio) is an important test for detecting early damage or any condition requiring monitoring [3]. Physicians must identify any elevated blood pressure or protein in the urine as warning signs requiring periodic follow-up.

Follow-up and Advanced Diagnosis

In certain cases, if routine laboratory tests do not provide a clear picture, doctors may recommend advanced procedures such as cystoscopy or ureteroscopy; these are clinical procedures that are planned carefully. These examinations, which differ from simple blood and urine tests, aim to directly detect obstructions or stones [2]. For details on basic examinations, you can review our comprehensive article on Kidney tests: When do we need urine and blood analysis to diagnose kidney disease? (Arabic).

When Should You Consult a Doctor Immediately?

Any signs indicating a severe urinary tract problem should not be ignored, regardless of the age group. Seek immediate medical attention if the following symptoms appear:

• Inability to urinate or feeling an uncomfortable fullness in the bladder.
• Visible bloody urine (red color) or blood clots.
• Severe pain or burning during urination that lasts for more than two days.
• High fever accompanied by chills, which may indicate a severe urinary tract infection [2].

Medical references

• Kidney Tests
• Cystoscopy & Ureteroscopy
• Chronic Kidney Disease Tests & Diagnosis
• Kidney Disease in Children - NIDDK
• Measurement of kidney function | UK Kidney Association