USMLE Normal Lab Values

Questions and Answers

What is the normal pH range?

7.35 - 7.45 (correct)

7.1 - 7.3

7.5 - 7.7

6.8 - 7.0

What is the normal range for pCO2?

33 - 45 mmHg

What is the normal range for pO2?

75 - 105 mm Hg

What is the commonly used normal range for SaO2?

95 - 100% Signup and view all the answers

What is the normal HCO3 range?

22 to 28 mEq/L Signup and view all the answers

What is the normal range for total serum calcium?

8.4 - 10.2 mg/dL Signup and view all the answers

What is the normal potassium level range?

3.5 - 5 mEq/L Signup and view all the answers

What is the normal sodium level range?

136 - 145 mEq/L Signup and view all the answers

What is the normal fasting blood glucose range?

70 - 110 mg/dL Signup and view all the answers

What is the normal range for random blood glucose?

80 - 120 mg/dL Signup and view all the answers

What is the normal 2-hour postprandial blood glucose level?

< 120 mg/dL Signup and view all the answers

1 hour post GTT test should be less than _____ mg/dL to be normal.

200 Signup and view all the answers

What is the normal Glycosylated Hemoglobin (HgbA1C) level?

≤ 6% Signup and view all the answers

What is the normal Prothrombin Time (PT)?

13 seconds Signup and view all the answers

What is the normal PTT?

35 seconds Signup and view all the answers

What is the normal INR for most patients?

1-2 Signup and view all the answers

Match the following hematocrit values with the corresponding gender:

Male = 41-53% Female = 36-46% Signup and view all the answers

Match the following hemoglobin values with the corresponding gender:

Male = 13.5-17.5 g/dL Female = 12.0-16.0 g/dL Signup and view all the answers

Match the following RBC count ranges with the corresponding gender:

Male = 4.3-5.9 million/mm³ Female = 3.5-5.5 million/mm³ Signup and view all the answers

What is the normal MCV range?

80-100 µm³ Signup and view all the answers

What is the normal MCH range?

25.4-34.6 pg/cell Signup and view all the answers

What is the normal MCHC range?

31-36% Hb/cell Signup and view all the answers

What is the normal platelet count range?

150,000-400,000/μL Signup and view all the answers

What is the normal WBC count range?

4500-11,000/mm³ Signup and view all the answers

What is the normal cholesterol level?

40 mg/dL Signup and view all the answers

Study Notes

Blood Gas and Acidity Values

pH: Normal range is 7.35 - 7.45, indicating acid-base balance.
pCO2: Normal values are between 33 - 45 mmHg, commonly referred to as 35 - 45 mmHg.
pO2: Expected range is 75 - 105 mmHg, usually represented as 80 - 100 mmHg.
SaO2: Expected saturation levels are typically 95 - 100%.

Electrolytes and Biochemical Parameters

HCO3: Normal bicarbonate level is between 22 to 28 mEq/L, crucial for acid-base balance.
Serum Calcium (Total): Normal levels range from 8.4-10.2 mg/dL; critical if above 12 mg/dL; commonly 9 - 11 mg/dL.
Potassium: Optimal range is 3.5 - 5 mEq/L, essential for cellular function.
Sodium: Normal sodium levels range from 136 - 145 mEq/L, usually used as 135 - 145 mEq/L.

Glucose and Hemoglobin Values

Fasting Blood Glucose: Value should be between 70-110 mg/dL, commonly referred to as 70 - 100 mg/dL.
Random Blood Glucose: Levels vary based on last meal; typically 80-120 mg/dL before meals and 100-140 mg/dL at bedtime; commonly kept < 125 mg/dL.
2 Hr Postprandial Blood Glucose: Normal value is < 120 mg/dL.
Glucose Tolerance Test (GTT): 1 hour post-test ≤ 200 mg/dL is normal, 2 hours post-test < 140 mg/dL indicates normal; values between 140-200 mg/dL suggest impaired glucose tolerance or prediabetes.
Glycosylated Hemoglobin (HgbA1C): Target is ≤ 6%, frequently cited range is 4 - 6 %.

Coagulation and Hematological Values

Prothrombin Time (PT): Normal result is 13 seconds, commonly noted as 9 to 12 seconds.
Partial Thromboplastin Time (PTT): Expected value is around 35 seconds.
International Normalized Ratio (INR): Normal range is 1-2; therapeutic target with Coumadin is 2 - 3.

Blood Composition Metrics

Hematocrit (Hct):
- Male: 41-53%, commonly used 42 - 52%.
- Female: 36-46%, commonly used 35 - 47%.
Hemoglobin (Hgb):
- Male: 13.5-17.5 g/dL, often referred to as 13 - 18 gm/dL.
- Female: 12.0-16.0 g/dL.
RBC (Erythrocyte Count):
- Male: 4.3-5.9 million/mm³, typically noted as 4.6-6.2 million/mm³.
- Female: 3.5-5.5 million/mm³.
Mean Corpuscular Volume (MCV): Normal size of RBCs is 80-100 µm³.
Mean Corpuscular Hemoglobin (MCH): Normal is 25.4-34.6 pg/cell, commonly noted as 27 - 31 pg/cell.
Mean Corpuscular Hemoglobin Concentration (MCHC): Normal concentration range is 31-36% Hb/cell, typically 32 - 36 g/dL.

Platelet and White Blood Cell Counts

Platelet Count: Confines between 150,000-400,000/μL, important for clotting.
WBC (Leukocyte Count): Normal range is 4,500-11,000/mm³, typically noted as 5,000 - 10,000/mm³.
Cholesterol: Desired levels are notably high, with a baseline of 40 mg/dL.

LDL

Low-Density Lipoprotein (LDL) values are commonly measured but specific normal ranges are not stated.

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Description

Test your knowledge of normal lab values essential for the USMLE exam. This quiz covers key measurements such as pH, pCO2, pO2, SaO2, HCO3, and serum calcium levels. Understanding these values is crucial for effective patient assessment and diagnosis.