Biochemistry

Biochemistry

Biochemistry involves the study of chemical processes within and relating to living organisms. In clinical practice, biochemistry tests are essential for assessing the function of various organs, detecting metabolic disorders,

and monitoring ongoing treatment. The following sections will discuss key biochemical tests, including Blood Glucose, Liver Function Tests (LFTs), Renal Function Tests (RFTs), Lipid Profile, and Electrolytes.

1. Blood Glucose (Fasting/Random)

Blood glucose tests measure the level of glucose (sugar) in the blood. Glucose is the primary energy source for the body’s cells, and maintaining its level within a normal range is crucial for health. Blood glucose can be measured either when fasting (after not eating for at least 8 hours) or at random times.

Normal Range Values:

• Fasting Blood Glucose: 70 to 99 milligrams per deciliter (mg/dL)
• Random Blood Glucose: Less than 140 mg/dL

Clinical Significance:

• Hyperglycemia (High Blood Glucose): Elevated blood glucose levels can indicate diabetes mellitus or impaired glucose tolerance. Chronic hyperglycemia can lead to serious complications like cardiovascular disease, kidney damage, and nerve damage.
• Hypoglycemia (Low Blood Glucose): Low blood glucose levels can occur due to excessive insulin use, prolonged fasting, or certain endocrine disorders. Symptoms of hypoglycemia include shakiness, sweating, confusion, and, if severe, can lead to loss of consciousness.

2. Liver Function Tests (LFTs)

Liver Function Tests (LFTs) are a group of blood tests that provide information about the state of a patient’s liver. The liver plays a vital role in metabolism, detoxification, and protein synthesis, and these tests can help diagnose liver diseases such as hepatitis, cirrhosis, and liver damage.

Components of LFTs:

• Alanine Aminotransferase (ALT): 7 to 56 units per liter (U/L)
• Aspartate Aminotransferase (AST): 10 to 40 U/L
• Alkaline Phosphatase (ALP): 44 to 147 U/L
• Gamma-Glutamyl Transferase (GGT): 9 to 48 U/L
• Total Bilirubin: 0.1 to 1.2 milligrams per deciliter (mg/dL)
• Albumin: 3.5 to 5.0 grams per deciliter (g/dL)
• Total Protein: 6.3 to 7.9 g/dL

Clinical Significance:

• Elevated ALT and AST: These enzymes are released into the bloodstream when liver cells are damaged, indicating liver inflammation or injury.
• Elevated ALP and GGT: These can indicate bile duct obstruction, liver disease, or bone disorders.
• Abnormal Bilirubin Levels: High bilirubin can lead to jaundice and indicate liver dysfunction, bile duct obstruction, or hemolysis.
• Low Albumin: May indicate chronic liver disease, kidney disease, or malnutrition.

3. Renal Function Tests (RFTs)

Renal Function Tests (RFTs) are a group of tests used to evaluate kidney function. The kidneys play a critical role in filtering waste from the blood, balancing fluids, and regulating electrolytes. These tests can help diagnose kidney disease and monitor kidney function in patients with chronic conditions.

Components of RFTs:

• Blood Urea Nitrogen (BUN): 7 to 20 mg/dL
• Serum Creatinine: 0.6 to 1.3 mg/dL (varies slightly by gender and age)
• Uric Acid: 3.5 to 7.2 mg/dL
• Glomerular Filtration Rate (GFR): 90 to 120 milliliters per minute (mL/min)

Clinical Significance:

• Elevated BUN: High levels may indicate kidney dysfunction, dehydration, or increased protein metabolism.
• Elevated Serum Creatinine: Indicates impaired kidney function or acute kidney injury.
• Low GFR: A low GFR is a sign of reduced kidney function and can indicate chronic kidney disease.
• Elevated Uric Acid: High levels may lead to gout or kidney stones and can indicate decreased kidney excretion.

4. Lipid Profile

A Lipid Profile is a panel of blood tests that measure different types of cholesterol and triglycerides in the blood. These tests are crucial for assessing cardiovascular risk and guiding treatment for conditions such as hyperlipidemia and coronary artery disease.

Components of Lipid Profile:

• Total Cholesterol: Less than 200 mg/dL
• Low-Density Lipoprotein (LDL) Cholesterol: Less than 100 mg/dL
• High-Density Lipoprotein (HDL) Cholesterol: 40 mg/dL or higher for men; 50 mg/dL or higher for women
• Triglycerides: Less than 150 mg/dL

Clinical Significance:

• High LDL Cholesterol: Known as “bad” cholesterol, high levels increase the risk of atherosclerosis, heart attack, and stroke.
• Low HDL Cholesterol: Known as “good” cholesterol, low levels are associated with an increased risk of cardiovascular disease.
• High Triglycerides: Elevated triglyceride levels can contribute to atherosclerosis and increase the risk of cardiovascular disease.

5. Electrolytes (Sodium, Potassium, Chloride)

Electrolytes are minerals in the blood and body fluids that carry an electric charge. They are vital for numerous physiological functions, including fluid balance, nerve transmission, and muscle contraction. The electrolyte panel typically includes measurements of sodium, potassium, and chloride.

Normal Range Values:

• Sodium (Na+): 135 to 145 milliequivalents per liter (mEq/L)
• Potassium (K+): 3.5 to 5.1 mEq/L
• Chloride (Cl-): 98 to 106 mEq/L

Clinical Significance:

• Hyponatremia (Low Sodium): Can cause symptoms like confusion, seizures, and muscle cramps, often due to fluid imbalance, heart failure, or kidney disease.
• Hypernatremia (High Sodium): Can lead to dehydration, thirst, confusion, and muscle twitching.
• Hypokalemia (Low Potassium): May result in muscle weakness, cramps, arrhythmias, and fatigue, often due to diuretic use or vomiting.
• Hyperkalemia (High Potassium): Can cause dangerous heart rhythms, muscle weakness, and potentially cardiac arrest.
• Hypochloremia (Low Chloride): Often occurs with low sodium and can lead to alkalosis.
• Hyperchloremia (High Chloride): Usually associated with acidosis or dehydration.

Summary Table of Normal Ranges

This article provides an in-depth overview of key biochemistry tests, including their normal ranges and clinical significance, making it easier to understand their role in diagnosing and managing various health conditions.