Lab Values

Ch 4 2025 book

What is point-of-care (POC) testing, and what are some examples?

Rapid testing performed at the site of patient care that provides quick results;

Cardiac enzymes, A1C, INR, and infection testing

What is therapeutic drug monitoring (TDM)?

Obtaining drug levels or other labs to monitor efficacy and safety

What does a CBC evaluate?

WBCs, RBCs, platelets, H/H

What does hemoglobin (Hgb) measure?

The oxygen-carrying protein in red blood cells

What does hematocrit (Hct) measure?

The proportion of RBCs in the blood

What is analyzed in a CBC with differential?

The different types of white blood cells

What does a BMP assess?

Electrolytes, glucose, renal function, and acid-base status (HCO3 or bicarb)

What tests are included in a CMP?

all labs from BMP + Albumin, ALT, AST, total bilirubin, and total protein

What is the primary purpose of the additional tests in a CMP?

To assess liver function

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What are the three major blood cell lines produced by stem cells in the bone marrow?

RBC

WBC

PLT

What is another name for WBCs and what about RBCs?

Leukocytes; erythrocytes

What is an immature red blood cell called?

Reticulocyte

What is an increase in ___ called?

1. WBCs

2. RBCs

3. platelets

1. Leukocytosis

2. Polycythemia

3. Thrombocytosis

What is a decrease in ___ called?

1. WBCs

2. RBCs /Hgb

3. platelets

1. Leukopenia

2. Anemia

3. Thrombocytopenia

What is myelosuppression?

A decrease in WBCs, RBCs, and platelets

What is agranulocytosis?

A decrease in granulocytes (neutrophils, basophils, and eosinophils)

Which WBCs are classified as granulocytes?

Neutrophils, basophils, and eosinophils

Which drugs are commonly associated with agranulocytosis?

Clozapine, propylthiouracil, methimazole, procainamide, carbamazepine, isoniazid, and sulfamethoxazole/trimethoprim

Which WBCs are not granulocytes?

Lymphocytes and monocytes

What is the normal_____ range?

1. total calcium

2. ionized calcium

1. 8.5–10.5 mg/dL

2. 4.5–5.1 mg/dL

When should corrected calcium be calculated?

When albumin is low (not needed for ionized calcium)

What can ______ calcium levels?

1. increase

2. decrease

1. Calcium supplements, vitamin D, and thiazide diuretics

2. Loop diuretics, bisphosphonates, cinacalcet, steroids, calcitonin, foscarnet, topiramate, and long-term heparin

What is the normal chloride (Cl) range and purpose?

95–106 mEq/L; assesses acid-base status and fluid balance

What is the normal magnesium (Mg) range?

1.3–2.1 mEq/L

What can _____ magnesium levels?

1. increase

2. decrease

1. Magnesium-containing antacids and laxatives

2. PPIs, diuretics, amphotericin B, foscarnet, echinocandins, diarrhea, and chronic alcohol use

What is the normal phosphate (PO4) range?

2.3–4.7 mg/dL

What can _____ phosphate levels?

1. increase

2. decrease

1. CKD

2. Phosphate binders, foscarnet, and oral calcium

What is the normal potassium (K) range?

3.5–5 mEq/L

What drug classes commonly increase potassium levels?

RAAS inhibitors, potassium supplements, calcineurin inhibitors, TMP-SMX, NSAIDs, and selected drugs (e.g., pentamidine, canagliflozin)

What drug classes commonly decrease potassium levels?

Diuretics, beta-2 agonists, insulin, sodium polystyrene sulfonate, steroids, and conivaptan

What is the normal sodium (Na) range?

135–145 mEq/L

What can ___ sodium levels?

1. increase

2. decrease

1. Hypertonic saline, tolvaptan, and conivaptan

2. Carbamazepine, oxcarbazepine, SSRIs, diuretics, and desmopressin

When should sodium be corrected before interpretation?

When hyperglycemia is present

What is the normal bicarbonate (HCO3−) range?

Venous: 24–30 mEq/L;

Arterial: 22–26 mEq/L

What is bicarbonate used to assess?

Acid-base status

What can _____ bicarbonate levels?

1. increase

2. decrease

1. Loop diuretics and systemic steroids

2. Topiramate, zonisamide, and salicylate overdose

What is the normal BUN range? and what is BUN used for?

7–20 mg/dL; With SCr (BUN:SCr ratio) to assess fluid status and renal function

What can increase BUN levels?

Renal impairment and dehydration

What is the normal serum creatinine (SCr) range?

0.6–1.3 mg/dL

What can increase SCr levels?

Renal dysfunction or nephrotoxic drugs (e.g., aminoglycosides, amphotericin B, cisplatin, cyclosporine, NSAIDs, tacrolimus, vancomycin)

Which drugs can falsely increase SCr?

TMP-SMX, H2RAs, and cobicistat

What can decrease SCr levels?

Low muscle mass, amputation, and hemodilution

What is the normal glucose range?

70–110 mg/dL

What is the normal anion gap (AG) range?

5–12 mEq/L

What does an increased anion gap suggest?

Metabolic acidosis

What is the normal WBC range?

4,000–11,000 cells/mm³

What is the primary use of the WBC count?

Diagnose and monitor infection and inflammation

What can _____ WBC count?

1. increase

2. decrease

1. Inflammation, stress, systemic steroids, colony-stimulating factors, and epinephrine

2. Clozapine, bone marrow-suppressing chemotherapy, carbamazepine, cephalosporins, immunosuppressants, procainamide, and vancomycin

What is the normal neutrophil range?

45–73%

What are neutrophils used to assess?

The likelihood of acute infection

What is ANC and what is it used for?

Absolute neutrophil count; used to assess for neutropenia

What are other names for neutrophils?

PMNs (polys) or segmented neutrophils (segs)

What is the normal band range? and what are bands?

3–5%

Immature neutrophils released from the bone marrow to fight infection

What is a left shift?

An increase in bands released from the BM to fight an infection

What is the normal eosinophil range? and what can increase them?

0–5%; Drug allergy, asthma, inflammation, and parasitic infection

What is the normal basophil range? and what can increase them?

0–1%;

Inflammation, hypersensitivity reactions, and leukemia

What is the normal lymphocyte range?

20–40%

What can ____ lymphocytes?

1. increase

2. decrease

1. Viral infections and lymphoma

2. Bone marrow suppression, HIV, and systemic steroids

What can decrease lymphocytes?

Bone marrow suppression, HIV, and systemic steroids

What is the normal monocyte range?

What can increase monocytes?

2–8%; Chronic infections, inflammation, and stress

What is the normal RBC range?

Males: 4.5–5.5 × 10⁶ cells/µL; Females: 4.1–4.9 × 10⁶ cells/µL

What can increase RBC count?

ESAs, smoking, and polycythemia

What can decrease RBC count?

Bone marrow-suppressing chemotherapy, low production, blood loss, deficiency anemias (B12/folate), hemolytic anemia, and sickle cell anemia

What is the normal hemoglobin (Hgb) range?

Males: 13.5–18 g/dL; Females: 12–16 g/dL

What can ____ hemoglobin?

1. increase

2. decrease

1. ESAs

2. Anemia and bleeding (including anticoagulants, antiplatelets, and fibrinolytics)

What is the normal hematocrit (Hct) range?

Males: 38–50%; Females: 36–46%

What is the normal MCV range?

80–100 fL

What does MCV measure?

The size and average volume of RBCs

What does an increased MCV indicate?

Macrocytic anemia (e.g., B12 or folate deficiency)

What does a decreased MCV indicate?

Microcytic anemia (e.g., iron deficiency)

What is the normal MCH range?

26–34 pg/cell

What is the normal MCHC range?

31–37 g/dL

What is the normal RDW range?

11.5–14.5%

What does RDW measure?

Variability in RBC size

What are MCV, MCHC, and RDW collectively called?

RBC indices

What is the normal iron range?

65–150 mcg/dL

What can increase iron levels?

Iron supplementation

What can decrease iron levels?

Blood loss or poor nutrition

What is the normal TIBC range?

250–400 mcg/dL

What is the normal transferrin level?

>200 mg/dL

What is the normal transferrin saturation (TSAT) range?

Males: 15–50%; Females: 12–45%

What is the normal ferritin range?

11–300 ng/mL

What is the normal erythropoietin range?

2–25 mIU/mL

What is the desirable total cholesterol (TC) level?

How long should a patient fast before a fasting lipid panel?

9–12 hours

What is the desirable LDL level?

What is the desirable HDL level?

≥60 mg/dL

What is the desirable non-HDL level?

How is non-HDL cholesterol calculated?

Total cholesterol − HDL

What is the desirable triglyceride (TG) level?

What labs are included in a lipid panel?

TC, HDL, LDL, and TG

What is the purpose of a lipid panel?

Assess cholesterol levels and cardiovascular risk

What is the normal lipoprotein(a) [Lp(a)] level?

What is the normal apolipoprotein B (ApoB) level?

What is the significance of elevated Lp(a) and ApoB?

Increased coagulation and cardiovascular disease risk

What is the normal C-reactive protein (CRP) range?

0–0.5 mg/dL

What does an elevated CRP indicate?

Inflammation and increased cardiovascular risk

What is a desirable coronary artery calcium (CAC) score?