CALT EXAM| 111 questions| with comprehensive answers,

CALT EXAM| 111 questions| with
comprehensive answers
Course
CALT
Question 1
A physician orders a Complete Blood Count (CBC) for a patient complaining of fatigue. Which
laboratory parameter is most useful in determining whether the patient has anemia?
A. Platelet count
B. White blood cell count
C. Hemoglobin concentration
D. Sodium level
Correct Answer: C. Hemoglobin concentration
Comprehensive Answer
Hemoglobin is the oxygen-carrying protein found inside red blood cells. A decreased
hemoglobin level is the primary laboratory indicator of anemia. While hematocrit and RBC
count also provide valuable information, hemoglobin is the standard measurement used to
diagnose anemia.
 Platelets evaluate blood clotting.
 White blood cells indicate infection or immune status.
 Sodium reflects electrolyte balance rather than oxygen-carrying capacity.
Normal adult hemoglobin values generally include:
 Men: 13.5–17.5 g/dL
 Women: 12.0–15.5 g/dL
A value below these ranges suggests anemia requiring further investigation.


Question 2
Which of the following is the most important step before collecting a blood specimen?
A. Wear gloves only
B. Label the specimen after collection

,C. Properly identify the patient
D. Prepare laboratory forms
Correct Answer: C. Properly identify the patient
Comprehensive Answer
Patient identification is the most critical safety step in specimen collection. The laboratory
professional should verify at least two patient identifiers, such as:
 Full name
 Date of birth
 Medical record number
Incorrect patient identification may lead to:
 Misdiagnosis
 Wrong treatment
 Blood transfusion errors
 Serious patient harm
Specimens should be labeled immediately after collection while still in the patient's presence.


Question 3
Which anticoagulant is commonly used for Complete Blood Count (CBC) testing?
A. Sodium citrate
B. Heparin
C. EDTA
D. Sodium fluoride
Correct Answer: C. EDTA
Comprehensive Answer
EDTA (Ethylenediaminetetraacetic acid) preserves blood cell morphology by preventing
coagulation through calcium chelation.
Tube color:
 Lavender (purple) top

,Uses include:
 CBC
 Blood smear preparation
 Differential counts
Other anticoagulants:
 Sodium citrate: coagulation studies
 Heparin: chemistry testing
 Sodium fluoride: glucose preservation


Question 4
Why is hand hygiene considered the single most effective infection prevention measure?
A. It reduces laboratory costs.
B. It replaces wearing gloves.
C. It interrupts the transmission of microorganisms.
D. It sterilizes equipment.
Correct Answer: C. It interrupts the transmission of microorganisms.
Comprehensive Answer
Hands are the primary route for transmitting infectious organisms. Proper hand hygiene removes
or destroys pathogens before they spread to:
 Patients
 Laboratory staff
 Equipment
 Specimens
Hand hygiene should be performed:
 Before patient contact
 After glove removal
 After specimen handling

,  Before leaving the laboratory
Alcohol-based hand rubs are effective unless hands are visibly soiled.


Question 5
A blood specimen becomes hemolyzed during collection. What is the most likely consequence?
A. Improved laboratory accuracy
B. Falsely elevated potassium levels
C. Lower glucose concentration only
D. Improved platelet count
Correct Answer: B. Falsely elevated potassium levels
Comprehensive Answer
Hemolysis occurs when red blood cells rupture, releasing intracellular contents into plasma.
Affected laboratory values include:
 Potassium ↑
 LDH ↑
 AST ↑
 Phosphate ↑
Hemolyzed specimens often require recollection because they may produce misleading results
that affect clinical decisions.
Common causes include:
 Using too small a needle
 Vigorous shaking
 Difficult venipuncture
 Drawing blood through an IV line


Question 6
Which biosafety practice should always be followed when handling blood specimens?