Liver Function Tests and Kidney Function Tests

Laboratory tests play a crucial role in diagnosing and monitoring various health conditions. Two of the most commonly conducted tests are Liver Function Tests (LFT) and Kidney Function Tests (KFT). Understanding the normal ranges and interpretations of these tests can help in assessing liver and kidney health effectively.

Liver Function Tests (LFTs)

Liver Function Tests help evaluate the overall health of the liver by measuring different enzymes, proteins, and substances in the blood.

Key Parameters and Their Normal Ranges

1. Alanine Aminotransferase (ALT/SGPT)
   • Normal Range: 7-56 U/L
   • Interpretation: Elevated levels may indicate liver damage due to hepatitis, fatty liver disease, or alcohol consumption.
2. Aspartate Aminotransferase (AST/SGOT)
   • Normal Range: 10-40 U/L
   • Interpretation: Higher levels may indicate liver or muscle damage. The AST/ALT ratio is often used to distinguish between liver and non-liver causes.
3. Alkaline Phosphatase (ALP)
   • Normal Range: 44-147 U/L
   • Interpretation: Elevated levels can suggest bile duct obstruction, liver disease, or bone disorders.
4. Total Bilirubin
   • Normal Range: 0.1-1.2 mg/dL
   • Interpretation: High levels may indicate liver dysfunction, hemolysis, or bile duct blockage.
5. Direct (Conjugated) Bilirubin
   • Normal Range: 0.0-0.3 mg/dL
   • Interpretation: Increased levels suggest cholestasis or hepatobiliary disease.
6. Albumin
   • Normal Range: 3.5-5.0 g/dL
   • Interpretation: Low albumin may indicate chronic liver disease, malnutrition, or kidney disease.
7. Total Protein
   • Normal Range: 6.0-8.3 g/dL
   • Interpretation: Decreased levels may be seen in liver disease and malnutrition, whereas increased levels can be due to dehydration or chronic infections.
8. Gamma-Glutamyl Transferase (GGT)
   • Normal Range: 9-48 U/L
   • Interpretation: Elevated levels can indicate alcohol-induced liver disease or bile duct obstructions.
9. Prothrombin Time (PT/INR)
   • Normal Range: PT: 11-13.5 seconds, INR: 0.8-1.1
   • Interpretation: Prolonged PT/INR may indicate liver disease or coagulation disorders.

Kidney Function Tests (KFTs)

Kidney Function Tests help assess how well the kidneys are filtering waste from the blood.

Key Parameters and Their Normal Ranges

1. Serum Creatinine
   • Normal Range: 0.6-1.3 mg/dL
   • Interpretation: Elevated levels suggest impaired kidney function or dehydration.
2. Blood Urea Nitrogen (BUN)
   • Normal Range: 7-20 mg/dL
   • Interpretation: Increased BUN indicates kidney dysfunction, dehydration, or high protein intake.
3. Urea
   • Normal Range: 20-40 mg/dL
   • Interpretation: Elevated levels may indicate kidney disease or high protein metabolism.
4. Glomerular Filtration Rate (GFR)
   • Normal Range: 90-120 mL/min/1.73m^2
   • Interpretation: Decreased GFR indicates chronic kidney disease (CKD) or kidney failure.
5. Electrolytes (Sodium, Potassium, Chloride, Bicarbonate)
   • Sodium (Na+): 135-145 mEq/L
   • Potassium (K+): 3.5-5.0 mEq/L
   • Chloride (Cl-): 98-107 mEq/L
   • Bicarbonate (HCO3-): 22-28 mEq/L
   • Interpretation: Imbalances in these electrolytes can indicate kidney dysfunction, dehydration, or metabolic disorders.
6. Urine Protein (Proteinuria Test)
   • Normal Range: Less than 150 mg/day
   • Interpretation: Increased protein in urine may indicate kidney damage or nephrotic syndrome.
7. Urine Creatinine Clearance
   • Normal Range: 85-135 mL/min
   • Interpretation: Lower values suggest impaired kidney filtration.

Conclusion

LFTs and KFTs provide essential insights into liver and kidney health. Any deviation from the normal range should be evaluated by a healthcare professional to determine the underlying cause and necessary interventions. Regular monitoring of these tests is crucial, especially for individuals with liver or kidney-related conditions.