Electrolytes, Urea, and Creatinine Test

1. Objective

To assess kidney function and electrolyte balance by measuring sodium (Na⁺), potassium (K⁺), chloride (Cl⁻), urea, and creatinine in blood.

2. Principle

Electrolytes (Na⁺, K⁺, Cl⁻): Measured using ion-selective electrodes (ISE) that detect specific ions.

Urea: Measured by the urease method, where urea is hydrolyzed to ammonia, which is then quantified.

Creatinine: Commonly measured by the Jaffe’s reaction, where creatinine reacts with picric acid in alkaline solution to form a colored complex.

3. Materials

Patient blood sample (serum or plasma)

Centrifuge

Ion-selective electrode analyzer

Urea reagent (urease)

Creatinine reagent (Jaffe’s solution)

Test tubes, pipettes

4. Procedure (Laboratory)

1. Blood was collected and centrifuged to obtain serum.

2. Serum was analyzed for:

Electrolytes using ion-selective electrode analyzer.

Urea by enzymatic method.

Creatinine by Jaffe’s method.

3. Results were compared to standard reference ranges.

5. Results (Normal Range)

Sodium (Na⁺): 135 – 145 mmol/L

Potassium (K⁺): 3.5 – 5.0 mmol/L

Chloride (Cl⁻): 98 – 107 mmol/L

Urea: 15 – 45 mg/dL (2.5 – 7.5 mmol/L)

Creatinine: Men: 0.7 – 1.3 mg/dL Women: 0.6 – 1.1 mg/dL

6. Uses

Diagnose and monitor kidney disease.

Assess fluid and electrolyte imbalance.

Monitor patients with hypertension, heart failure, or dehydration.

Evaluate response to treatment in renal impairment.

7. Consultation

Abnormal electrolytes may suggest dehydration, acidosis, alkalosis, or adrenal disorders.

High urea/creatinine indicates reduced kidney function.

Patients were advised to follow up with a nephrologist for proper management.