Chapter 4 : Diagnostic Metrics Dissecting Laboratory Values

What percentage of WBCs are basophils? A. 0-2% B. 45-75% C. 18-45% D. 0-7%

A. 0-2% Rationale: Basophils are the least common circulating granulocyte.

Eosinophils normally make up what percentage of the WBC count? A. 0-7% B. 1-10% C. 18-45% D. 45-75%

A. 0-7% Rationale: Eosinophils are typically present in very low quantities unless stimulated by allergens or parasites.

What is the normal hemoglobin range for adult males? A. 14-18 g/dL B. 37-47% C. 150,000-400,000/mcL D. 4,500-10,500 cells/mcL E. 4.2-5.4 million/mcL

A. 14-18 g/dL Rationale: Males have higher hemoglobin due to higher testosterone and RBC production.

What is the normal chloride range? A. 95-105 mEq/L B. 0.6-1.4 mg/dL C. 135-145 mEq/L D. 3.5-5.0 mEq/L E. 1.5-2.5 mEq/L F. 3.0-4.5 mEq/L G. 8.8-10.4 mg/dL H. 6-23 mg/dL

A. 95-105 mEq/L Rationale: Chloride helps maintain acid-base balance and parallels sodium levels.

What is the normal creatinine range? A. 95-105 mEq/L B. 0.6-1.4 mg/dL C. 135-145 mEq/L D. 3.5-5.0 mEq/L E. 1.5-2.5 mEq/L F. 3.0-4.5 mEq/L G. 8.8-10.4 mg/dL H. 6-23 mg/dL

B. 0.6-1.4 mg/dL Rationale: Creatinine reflects kidney filtration efficiency and rises with renal impairment.

What is the normal monocyte percentage? A. 18-45% B. 1-10% C. 45-75% D. 0-2%

B. 1-10% Rationale: Monocytes are a smaller fraction of circulating WBCs.

What is the normal percentage range for lymphocytes? A. 45-75% B. 18-45% C. 0-7% D. 1-10%

B. 18-45% Rationale: This is the standard reference range for lymphocytes on a CBC differential.

What is the normal hematocrit range for adult females? A. 14-18 g/dL B. 37-47% C. 150,000-400,000/mcL D. 4,500-10,500 cells/mcL E. 4.2-5.4 million/mcL

B. 37-47% Rationale: Female hematocrit is lower than male due to lower androgen levels and lower RBC mass.

Eosinophils are most associated with which condition? A. Fungal infections B. Allergic reactions and parasitic infections C. Viral infections D. Trauma

B. Allergic reactions and parasitic infections Rationale: Eosinophils increase in IgE-mediated allergy, asthma, and helminth infections.

Lymphocytes are most elevated in which type of infection? A. Bacterial B. Viral C. Parasitic D. Allergic

B. Viral Rationale: Lymphocytes regulate adaptive immunity and increase with viral infections.

What is the normal serum sodium range? A. 95-105 mEq/L B. 0.6-1.4 mg/dL C. 135-145 mEq/L D. 3.5-5.0 mEq/L E. 1.5-2.5 mEq/L F. 3.0-4.5 mEq/L G. 8.8-10.4 mg/dL H. 6-23 mg/dL

C. 135-145 mEq/L Rationale: Sodium is the major extracellular cation and tightly regulated for fluid balance.

What is the normal platelet count in adults? A. 14-18 g/dL B. 37-47% C. 150,000-400,000/mcL D. 4,500-10,500 cells/mcL E. 4.2-5.4 million/mcL

C. 150,000-400,000/mcL Rationale: This range reflects normal thrombocyte levels needed for clotting.

Neutrophils normally make up what percentage of the WBC differential? A. 1-10% B. 18-45% C. 45-75% D. 0-7%

C. 45-75% Rationale: They form the largest portion of circulating white blood cells.

What type of infection do neutrophils primarily respond to? A. Viral infections B. Allergic reactions C. Bacterial and fungal infections D. Chronic inflammatory conditions

C. Bacterial and fungal infections Rationale: Neutrophils are first-line responders in acute inflammation and are the dominant cell in bacterial and fungal infections.

What does the presence of elevated band cells indicate? A. Viral infection B. Allergic reaction C. Immature neutrophils (left shift) D. Chronic inflammation

C. Immature neutrophils (left shift) Rationale: Bands indicate early release of neutrophils from bone marrow during acute infection.

Basophils are associated with which response? A. Phagocytosis B. Viral defense C. Inflammatory response and histamine release D. Parasitic infection

C. Inflammatory response and histamine release Rationale: Basophils release histamine, heparin, and play a role in allergic inflammation.

Which cell type differentiates into macrophages in tissues? A. Neutrophils B. Lymphocytes C. Monocytes D. Basophils

C. Monocytes Rationale: Monocytes circulate briefly then become macrophages that clean up debris and phagocytose pathogens.

What is the normal serum phosphorus range? A. 95-105 mEq/L B. 0.6-1.4 mg/dL C. 135-145 mEq/L D. 3.5-5.0 mEq/L E. 1.5-2.5 mEq/L F. 3.0-4.5 mEq/L G. 8.8-10.4 mg/dL H. 6-23 mg/dL

F. 3.0-4.5 mEq/L Rationale: Phosphorus is required for ATP, bone metabolism, and acid-base buffering.

What is the normal serum calcium range? A. 95-105 mEq/L B. 0.6-1.4 mg/dL C. 135-145 mEq/L D. 3.5-5.0 mEq/L E. 1.5-2.5 mEq/L F. 3.0-4.5 mEq/L G. 8.8-10.4 mg/dL H. 6-23 mg/dL

G. 8.8-10.4 mg/dL Rationale: Calcium regulates muscle contraction, nerve transmission, and cardiac rhythm.

What is the normal BUN range? A. 95-105 mEq/L B. 0.6-1.4 mg/dL C. 135-145 mEq/L D. 3.5-5.0 mEq/L E. 1.5-2.5 mEq/L F. 3.0-4.5 mEq/L G. 8.8-10.4 mg/dL H. 6-23 mg/dL

H. 6-23 mg/dL Rationale: BUN increases with dehydration, high protein intake, and renal dysfunction.

A patient would likely require PRBC transfusion at what Hgb level?

Transfusion at <7 g/dL

After reviewing your patient's labs, you notice that their potassium level is 2.7 mEq/L. When looking at their ECG, what would you expect to find?

U waves ​

Chvostek's sign is associated with which electrolyte abnormality?

hypocalcemia

Which of the following patients would you anticipate being at the highest risk of developing hypernatremia? 56-year-old male with cancer of the lung and SIADH 48-year-old female with bacterial pneumonia, fever, and diaphoresis 73-year-old female with CHF taking loop diuretics 26-year-old male with acute diarrhea and vomiting

48-year-old female with bacterial pneumonia, fever, and diaphoresis

What is the normal serum potassium range? A. 95-105 mEq/L B. 0.6-1.4 mg/dL C. 135-145 mEq/L D. 3.5-5.0 mEq/L E. 1.5-2.5 mEq/L F. 3.0-4.5 mEq/L G. 8.8-10.4 mg/dL H. 6-23 mg/dL

D. 3.5-5.0 mEq/L Rationale: Potassium is critical for cardiac conduction and neuromuscular stability.

What is the normal WBC count? A. 14-18 g/dL B. 37-47% C. 150,000-400,000/mcL D. 4,500-10,500 cells/mcL E. 4.2-5.4 million/mcL

D. 4,500-10,500 cells/mcL Rationale: This reflects the expected circulating leukocyte count in a healthy adult.

Bands should normally be less than what percentage? A. 18-45% B. 45-75% C. 0-2% D. <4%

D. <4% Rationale: Bands normally make up a very small portion of neutrophils unless infection triggers accelerated production.

You have a 9-year-old female patient. Her current hematocrit (Hct) is 59%, serum Na+ is 158 mEq/L, and Cl- is 121 mEq/L What is the most likely cause of these findings? Normal finding in a pediatric patient Fluid overload Acute renal failure Dehydration

Dehydration is the most likely cause of these findings, as the elevated hematocrit, serum sodium (Na+cap N a raised to the positive power𝑁𝑎+), and chloride (Cl−cap C l raised to the negative power𝐶𝑙−) levels all point to a state of hemoconcentration due to fluid loss. An elevated hematocrit is a sign of reduced blood plasma volume, while high sodium and chloride levels indicate that the body has less fluid to dilute them. Dehydration: When the body loses too much fluid, the concentration of red blood cells in the blood increases, leading to a high hematocrit. Similarly, the concentration of electrolytes like sodium and chloride increases as there is less water to dilute them. Fluid overload: This would cause the opposite effect, with a lower hematocrit and a tendency towards lower sodium and chloride levels due to dilution. Acute renal failure: This condition can have various effects on electrolytes, but a primary symptom is often decreased urine output, which can lead to an accumulation of waste products and potentially electrolyte imbalances, but a high hematocrit and sodium level are not its primary indicators. Normal finding in a pediatric patient: The findings are not normal for a pediatric patient. A normal hematocrit is significantly lower than 59%, and serum sodium is typically in the range of 135-145 mEq/L.

What is the normal magnesium range? A. 95-105 mEq/L B. 0.6-1.4 mg/dL C. 135-145 mEq/L D. 3.5-5.0 mEq/L E. 1.5-2.5 mEq/L F. 3.0-4.5 mEq/L G. 8.8-10.4 mg/dL H. 6-23 mg/dL

E. 1.5-2.5 mEq/L Rationale: Magnesium is essential for ATP, nerve conduction, and neuromuscular stability.

What is the normal RBC count for adult females? A. 14-18 g/dL B. 37-47% C. 150,000-400,000/mcL D. 4,500-10,500 cells/mcL E. 4.2-5.4 million/mcL

E. 4.2-5.4 million/mcL Rationale: Female RBC counts run slightly lower than males due to lower testosterone-driven erythropoiesis.

You have administered 3 units of PRBCs. Your patient's initial Hgb & Hct (H&H) was 5 g/dL and 18 %. You would expect their H&H to increase to:

Hgb 8 g/dL & Hct 27 % Calculation Expected increase per unit: Each unit of packed red blood cells (PRBCs) is expected to raise the hemoglobin (Hgb) by approximately 1 g/dL and the hematocrit (Hct) by about 3%. Total increase after 3 units:Hgb increase: 1 g/dL/unit×3 units=3 g/dL1 g/dL/unit cross 3 units equals 3 g/dL1 g/dL/unit×3 units=3 g/dLHct increase: 3% per unit×3 units=9%3 % per unit cross 3 units equals 9 %3% per unit×3 units=9% Final H&H values:Initial Hgb: 5 g/dLExpected final Hgb: 5 g/dL+3 g/dL=8 g/dL5 g/dL plus 3 g/dL equals 8 g/dL5 g/dL+3 g/dL=8 g/dLInitial Hct: 18%Expected final Hct: 18%+9%=27%18 % plus 9 % equals 27 %18%+9%=27%