Clinical Lab Tests – Easy Notes (Vocabulary Flashcards)

Vocabulary flashcards covering key lab test concepts, ranges, and interpretations from the notes.

Reference Range

Normal limits for a lab value; varies by age, gender, race, and lab; results outside this range may indicate a problem.

Critical Test Value

A result that is dangerously outside the reference range and may be life-threatening; must be reported immediately.

Complete Blood Count (CBC)

A panel that includes WBCs, RBCs, and platelets to assess blood health.

WBC Count

White blood cell count; normal range 3.9–11.7 × 10³/mcL; high = leukocytosis (infection, stress, trauma); low = leukopenia (immune suppression, bone marrow disease).

Leukocytosis

High WBC count typically due to infection, stress, or trauma.

Leukopenia

Low WBC count often due to immune suppression or bone marrow disease.

Neutrophils (WBC differential)

Normally 40–75% of WBCs; ↑ in bacterial infection; ↓ in bone marrow disease.

Lymphocytes (WBC differential)

Normally 20–45% of WBCs; ↑ in viral infection; ↓ in immune issues.

CD4 T-cells

Subset of lymphocytes; typically 31–60% of lymphocytes; ↓ in HIV; <200 cells/µL indicates AIDS risk.

Eosinophils

Normally 0–6% of WBCs; ↑ in allergies or parasitic infections.

Basophils

Normally 0–1% of WBCs; ↑ can be seen with allergies.

Monocytes

Normally 2–10% of WBCs; ↑ in response to foreign material invasion.

RBC Count

Red blood cell count; Men 4.4–5.9 × 10⁶/mcL; Women 3.8–5.2 × 10⁶/mcL; low = anemia; high = polycythemia.

Hemoglobin (Hb)

Oxygen-carrying protein in RBCs; Men 13.3–17.7 g/dL; Women 11.7–15.7 g/dL.

Hematocrit (Hct)

Percentage of blood volume that is RBCs; Men 40–52%; Women 35–47%.

Sodium (Na⁺)

Normal 136–145 mEq/L;

Potassium (K⁺)

Normal 3.5–5.0 mEq/L;

Chloride (Cl⁻)

Normal 98–106 mEq/L;

Carbon Dioxide / Bicarbonate (CO₂)

Normal 22–29 mEq/L;

Calcium (Ca)

Total calcium normal range 4.5–5.25 mEq/L; critical

Ionized Calcium (Ca²⁺)

Active form of calcium; normal 2.2–2.7 mEq/L; critical

Glucose

Normal 70–139 mg/dL; >200 with symptoms suggests diabetes.

Anion Gap

Normal 4–12 mmol/L; increased value suggests metabolic acidosis.

Lactate

Normal 0.7–2.1 mEq/L; >4 indicates tissue hypoxia or sepsis.

Liver Enzymes (ALT, AST)

Elevated levels suggest liver damage; also assess bilirubin and albumin for liver function.

Pancreatic Enzymes (Amylase, Lipase)

Elevated levels suggest pancreatitis.

CPK Isoforms

CPK-1 (brain/lung), CPk-2 (heart), CPK-3 (skeletal muscle) — indicate tissue injury location.

Troponin-I

Elevated with myocardial infarction (heart attack).

BNP

Brain natriuretic peptide; elevated with heart failure; levels >900 suggest severe failure.

Platelets

Blood cells essential for clotting; low = bleeding risk; high = clotting risk.

PT/INR

PT/INR assess coagulation; INR normal ~0.9–1.3; INR around 5 indicates high bleeding risk.

D-Dimer

Marker that detects clots (DVT, PE, DIC).

Protein C

A protein that regulates clot breakdown; abnormalities affect thrombosis risk.

Procalcitonin (PCT)

Biomarker for bacterial infection; <0.1 ng/mL normal; ~0.5 ng/mL suggests sepsis is likely.

Sputum Gram Stain

Examines bacteria type and shape in sputum samples.

Culture

Identifies organism and antibiotic sensitivity to guide therapy.

Acid-Fast Test

Detects Mycobacterium tuberculosis (TB).

Xpert MTB/RIF

Rapid TB test that also detects drug resistance.

Viral Testing

Uses antigen or molecular assays (NAAT) to detect viral infections.

Sweat Chloride Test

Newborn or patient test for cystic fibrosis risk; results: ≥60 mmol/L CF; 30–60 borderline; <29 unlikely CF.