Clinical Lab Values Overview

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Questions and Answers

What condition is associated with metabolic or respiratory acidosis?

Hypokalemia

Respiratory alkalosis

Hyperkalemia (correct)

Cushing disease

Which medication is commonly linked to causing hypokalemia?

Thiazide diuretics (correct)

Albuterol

Potassium-sparing diuretics

Lantifungal

Patients with severe diarrhea are likely to develop which of the following conditions?

Metabolic acidosis

Respiratory acidosis

Hyperkalemia

Hypokalemia (correct)

Which of the following medications may contribute to hyperkalemia?

ACE inhibitors Signup and view all the answers

In a patient with low potassium levels, which mineral should typically be repleted first?

Magnesium Signup and view all the answers

What condition might lead to hyperkalemia due to renal failure?

Dehydration Signup and view all the answers

What is a common cause of hypokalemia related to alcohol consumption?

Respiratory alkalosis Signup and view all the answers

What is one potential cause of laboratory error?

Improper patient preparation Signup and view all the answers

Which of the following represents a function of sodium?

Assisting in fluid balance Signup and view all the answers

What is the normal range for potassium levels in mmol/L?

3.5 – 5.0 Signup and view all the answers

Hyponatremia can result from which of the following conditions?

Excess fluid accumulation Signup and view all the answers

Why might a repeat test be necessary?

To confirm previous errors or anomalies Signup and view all the answers

What is the role of potassium in the human body?

Nerve impulse transmission Signup and view all the answers

What is the normal sodium range in mEq/L?

135 – 147 Signup and view all the answers

Which condition can most likely lead to hypernatremia?

Dehydration Signup and view all the answers

What is a common characteristic of laboratory values across different patients?

Normal values can vary based on factors like age and weight Signup and view all the answers

What is the significance of a Comprehensive Metabolic Panel compared to a Basic Metabolic Panel?

Tests for a wider range of metabolic functions Signup and view all the answers

What electrolyte disturbance is characterized by serum potassium levels greater than 5 mmol/L?

Hyperkalemia Signup and view all the answers

Which aspect can influence variations in laboratory test results?

Various biological factors like weight and height Signup and view all the answers

What is the primary reason sodium levels need to be monitored?

To understand fluid balance in the body Signup and view all the answers

Study Notes

Clinical Pearls

Normal lab values differ between labs and patients.
Variations can occur due to techniques, reagents, age, gender, weight, and height.
Lab errors, though uncommon, can happen.
Potential causes include technical errors, improper calculations, inadequate specimens, incorrect sampling times, and medication interference.
If an error is suspected, repeat the test.

Introduction

Basic Metabolic Panel (BMP) or Chem-7, and Comprehensive Metabolic Panel (CMP) are initial lab tests.
BMP includes sodium, potassium, chloride, carbon dioxide, glucose, blood urea nitrogen (BUN), and serum creatinine.
CMP includes BMP plus albumin, alkaline phosphatase, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, calcium, and magnesium/phosphorus.

Sodium (Na+)

Normal range: 135 - 147 mEq/L.
Most prevalent cation in extracellular fluid.
Important for serum osmolarity, fluid balance, and acid-base balance.
Crucial for nerve impulse transmission by maintaining electrical potential.

Clinical Significance - Sodium

Hypernatremia: Increased sodium intake or fluid loss (e.g., gastroenteritis, diabetes insipidus, hyperaldosteronism).
Hyponatremia: Decreased total body sodium or excess body water (e.g., heart failure, chronic renal failure, syndrome of inappropriate antidiuretic hormone secretion (SIADH), severe burns).

Potassium (K+)

Normal range: 3.5 – 5 mmol/L.
Main intracellular cation.
Important for nerve excitability, acid-base balance, and muscle function.
Serum potassium levels aren't always a perfect indicator of overall potassium balance.
Significant effects on cardiac and neuromuscular function.

Clinical Significance - Potassium

Hyperkalemia: Metabolic or respiratory acidosis, renal failure, dehydration, medications (ACE inhibitors, potassium supplements).
Hypokalemia: Severe diarrhea/vomiting, respiratory alkalosis, alcohol abuse, Cushing's disease, medications (thiazide/loop diuretics, amphotericin B, insulin, albuterol).

Potassium - Magnesium

Potassium and magnesium interact in the body's systems.
Magnesium is involved in maintaining potassium balance.

Chloride (Cl-)

Normal range: 95 – 105 mEq/L.
Main extracellular anion.
Passive role in fluid balance and acid-base balance.

Clinical Significance - Chloride

Hyperchloremia: Metabolic acidosis, respiratory alkalosis, dehydration, diabetes insipidus, renal disorders.
Hypochloremia: Prolonged vomiting, metabolic alkalosis, heart failure, SIADH, use of acid suppressants (H2 blockers, proton-pump inhibitors).

Carbon Dioxide (CO2)

Normal range: 22 – 28 mEq/L.
Represents the sum of dissolved carbon dioxide and bicarbonate ions (HCO3-) in serum (also known as bicarbonate or bicarb level).
Regulates physiological pH.

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Description

This quiz covers key concepts related to clinical lab values, including variations due to patient factors and common lab tests such as BMP and CMP. Test your understanding of sodium levels and the implications of lab errors. Challenge yourself with important clinical pearls that every healthcare professional should know.