I85PREP
⌘ K
ASCP MLA study materials
ASCP MLA study resources

ASCP MLA practice questions

One question at a time. Build your ASCP MLA understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Specimen Collection and Processing

In the standard order of draw for venipuncture, which tube is collected immediately after blood culture bottles?

  1. Lavender EDTA tube
  2. Gray sodium fluoride tube
  3. Green heparin tube
  4. Light blue sodium citrate tube Correct answer.

Explanation

The standard order of draw begins with blood culture bottles, followed by light blue citrate, serum, heparin, EDTA, and gray tubes. Collecting citrate tubes early prevents contamination from additives in later tubes.

Question 2Specimen Collection and Processing

What is the maximum time a tourniquet should remain in place during venipuncture?

  1. 30 seconds
  2. 1 minute Correct answer.
  3. 3 minutes
  4. 5 minutes

Explanation

A tourniquet should be released within 1 minute to avoid hemoconcentration, hemolysis, and falsely elevated potassium and protein results. If more time is needed, the tourniquet should be released and reapplied.

Question 3Specimen Collection and Processing

Where should a capillary puncture be performed on an adult finger?

  1. Center of the fingertip
  2. Lateral side of the distal phalanx Correct answer.
  3. Over the distal joint crease
  4. Tip of the thumb

Explanation

The lateral side of the distal phalanx is less vascularly dense and has fewer nerve endings, reducing pain and callus formation. The center of the fingertip and joint creases are avoided because they are more sensitive and prone to injury.

Question 4Specimen Collection and Processing

Which needle gauge is most commonly used for routine adult venipuncture?

  1. 30 G
  2. 18 G
  3. 21 G Correct answer.
  4. 25 G

Explanation

A 21-gauge needle provides adequate blood flow for most adult veins while minimizing hemolysis. Larger 18-gauge needles are used for blood donation, and 25-gauge or smaller needles are reserved for small veins or pediatric patients.

Question 5Specimen Collection and Processing

How many times should a lavender EDTA tube be inverted after collection?

  1. 5 to 6 times
  2. 2 to 3 times
  3. 8 to 10 times Correct answer.
  4. 15 to 20 times

Explanation

Lavender EDTA tubes require 8 to 10 gentle inversions to mix the anticoagulant thoroughly without causing hemolysis. Inverting too few times can allow microclots to form.

Question 6Specimen Collection and Processing

What is the minimum patient identification requirement before specimen collection?

  1. Room number and bed number
  2. Patient's insurance number
  3. One identifier spoken by the patient
  4. Two independent identifiers Correct answer.

Explanation

Two independent identifiers, such as full name and date of birth, must be verified against the request and armband. Room or bed numbers are not acceptable identifiers because they can change.

Question 7Specimen Collection and Processing

A patient is instructed to fast before a lipid panel. How long should the fast typically last?

  1. 2 to 4 hours
  2. 8 to 12 hours Correct answer.
  3. 24 hours
  4. 48 hours

Explanation

A typical fasting lipid panel requires an 8- to 12-hour fast to accurately assess triglycerides and calculated LDL. Prolonged fasting beyond 12 hours is generally unnecessary and may be difficult for patients.

Question 8Specimen Collection and Processing

Which specimen is best for routine sputum culture?

  1. Nasal drainage
  2. Throat swab
  3. Saliva collected after brushing teeth
  4. Early morning deep-cough specimen Correct answer.

Explanation

An early morning deep-cough specimen is most likely to contain lower respiratory tract secretions and is preferred for sputum culture. Saliva is not acceptable because it is contaminated with oral flora.

Question 9Specimen Collection and Processing

A light blue sodium citrate tube must be filled to the indicated line because:

  1. Overfilling causes hemolysis and falsely shortens clotting times
  2. The tube contains no anticoagulant
  3. The line indicates the maximum volume for pediatric patients
  4. Underfilling increases the anticoagulant-to-blood ratio and can falsely prolong clotting times Correct answer.

Explanation

Citrate tubes are designed for a 9:1 blood-to-anticoagulant ratio. Underfilling leaves excess citrate relative to calcium, which can falsely prolong coagulation tests such as PT and aPTT.

Question 10Specimen Collection and Processing

Which practice most effectively prevents hemolysis during venipuncture?

  1. Shaking the tube vigorously after collection
  2. Allowing the tube to fill by vacuum and mixing gently Correct answer.
  3. Drawing blood through an IV line that was just flushed
  4. Using a 25-gauge needle for all adult draws

Explanation

Letting the vacuum fill the tube and mixing by gentle inversion prevents mechanical damage to red blood cells. Small needles, vigorous shaking, and drawing through recently flushed lines increase hemolysis risk.

Question 11Specimen Collection and Processing

When should blood cultures be collected relative to antibiotic administration?

  1. Immediately after the first antibiotic dose
  2. Before antibiotics are started Correct answer.
  3. At any time, because antibiotics do not affect cultures
  4. Only after 48 hours of antibiotic therapy

Explanation

Blood cultures should be collected before antibiotics begin whenever possible, because antibiotics can reduce the number of viable organisms. If therapy has already started, collection may still be indicated but recovery may be reduced.

Question 12Specimen Collection and Processing

When multiple tubes of cerebrospinal fluid are collected, which tube is typically used for cell count and differential?

  1. Tube 1
  2. Tube 3 Correct answer.
  3. Tube 2
  4. Tube 4

Explanation

CSF tubes are usually distributed by purpose: tube 1 for chemistry, tube 2 for microbiology, tube 3 for hematology, and tube 4 for additional studies. Tube 3 is preferred for cell counts because earlier tubes may contain traumatic blood.

Question 13Specimen Collection and Processing

A specimen for cold agglutinin testing should be transported:

  1. At room temperature
  2. Frozen
  3. At 37°C Correct answer.
  4. On ice

Explanation

Cold agglutinins can cause red cell agglutination at room temperature or below, so the specimen must be kept warm at 37°C during transport and processing. Chilling the sample can falsely lower the result.

Question 14Specimen Collection and Processing

Which condition is required for transport of a blood ammonia specimen?

  1. Keep at room temperature
  2. Protect from light only
  3. Place on ice and transport immediately Correct answer.
  4. Freeze within 1 hour

Explanation

Ammonia concentrations rise as blood cells metabolize proteins, so the specimen should be placed on ice and transported promptly. Delay or warming can falsely elevate ammonia results.

Question 15Specimen Collection and Processing

Why must air bubbles be removed from a blood gas syringe immediately after collection?

  1. Air bubbles make the sample unsuitable for electrolytes only
  2. Air bubbles increase the sample's carbon dioxide content
  3. Air bubbles cause clot formation
  4. Air bubbles alter pH and oxygen/carbon dioxide measurements Correct answer.

Explanation

Air bubbles equilibrate with the blood and can change pH, oxygen, and carbon dioxide values. The syringe should be sealed and mixed gently after expelling all air.

Question 16Specimen Collection and Processing

Which tube is preferred for glucose testing when the specimen cannot be analyzed promptly?

  1. Light blue citrate
  2. Gray sodium fluoride Correct answer.
  3. Green heparin
  4. Lavender EDTA

Explanation

Sodium fluoride in gray tubes inhibits glycolysis, preserving glucose concentration when analysis is delayed. Heparin and EDTA do not effectively prevent glucose loss.

Question 17Specimen Collection and Processing

A serum bilirubin specimen should be protected from light because:

  1. Light destroys bilirubin Correct answer.
  2. Light alters glucose
  3. Light increases bilirubin
  4. Light causes hemolysis

Explanation

Bilirubin is photosensitive and degrades when exposed to light, especially direct sunlight. Specimens should be wrapped in foil or placed in a dark container and analyzed promptly.

Question 18Specimen Collection and Processing

For therapeutic drug monitoring, a trough level is collected:

  1. Immediately before the next dose Correct answer.
  2. 30 minutes after the dose
  3. At any random time
  4. At the peak of drug absorption

Explanation

A trough level measures the lowest drug concentration and is drawn immediately before the next scheduled dose. Peak levels are drawn at specified times after administration.

Question 19Specimen Collection and Processing

During a 24-hour urine collection, the specimen should generally be:

  1. Discarded after each void
  2. Frozen immediately
  3. Refrigerated or preserved as instructed Correct answer.
  4. Kept at room temperature

Explanation

Most 24-hour urine collections are refrigerated or collected with an appropriate preservative to prevent bacterial growth and analyte degradation. The entire volume must be saved and mixed before analysis.

Question 20Specimen Collection and Processing

Which precaution is most important when collecting a stool specimen for ova and parasites?

  1. Refrigerate for 24 hours before transport
  2. Collect in a sterile blood culture bottle
  3. Mix with water
  4. Avoid contamination with urine or water Correct answer.

Explanation

Urine and water can destroy or dilute parasites and interfere with detection. The specimen should be collected in a clean container and transported promptly or preserved as instructed.

Question 21Specimen Collection and Processing

What is the correct order of draw for capillary blood collection when multiple tubes are needed?

  1. Other additive, serum, blood gas, EDTA
  2. Serum, EDTA, blood gas, other additive
  3. Blood gas, EDTA, other additive, serum Correct answer.
  4. EDTA, blood gas, serum, other additive

Explanation

Capillary order of draw begins with blood gas tubes, then EDTA, then other additive tubes, and finally serum tubes. This sequence minimizes cross-contamination between additives.

Question 22Specimen Collection and Processing

A light blue citrate tube is drawn immediately after a green heparin tube using the same butterfly setup. What is the most likely effect?

  1. The sample is unaffected
  2. Clotting times may be falsely shortened
  3. Hemolysis will always occur
  4. Clotting times may be falsely prolonged Correct answer.

Explanation

Heparin carryover into a citrate tube inhibits clotting and can falsely prolong PT and aPTT results. Following the correct order of draw prevents this contamination.

Question 23Specimen Collection and Processing

What is the recommended blood volume per culture set for an adult?

  1. 20 mL Correct answer.
  2. 1 to 2 mL
  3. 5 mL
  4. 50 mL

Explanation

Adult blood culture sets typically require about 20 mL of blood, usually 10 mL per bottle, to improve organism recovery. Lower volumes reduce sensitivity.

Question 24Specimen Collection and Processing

For newborn screening, blood is collected by heel stick onto filter paper. Which action is correct?

  1. Touch the filter paper to the puncture site repeatedly
  2. Collect from the central area of the heel
  3. Use a capillary tube to transfer blood to the card
  4. Apply a large drop and allow it to soak through both sides Correct answer.

Explanation

A large blood drop should be applied directly to the filter paper and allowed to soak completely through to the reverse side. Repeated touching or capillary tube transfer can cause layering and invalid specimens.

Question 25Specimen Collection and Processing

When transferring blood from a syringe into a citrate tube for coagulation testing, what is the correct technique?

  1. Remove the needle and gently dispense blood down the tube wall Correct answer.
  2. Shake the syringe before transfer
  3. Inject forcefully through the needle to mix
  4. Transfer only after the blood has clotted

Explanation

The needle should be removed before dispensing to reduce hemolysis, and the blood should be delivered gently down the tube wall. The tube must then be filled to the line and inverted to mix.

Question 26Specimen Collection and Processing

During a routine venipuncture, how long should the tourniquet remain in place before it is released?

  1. No longer than 5 minutes
  2. No longer than 1 minute Correct answer.
  3. As long as needed to locate a suitable vein
  4. No longer than 3 minutes

Explanation

Tourniquet application should not exceed 1 minute, and the tourniquet should be released as soon as blood flow is established. Prolonged stasis causes hemoconcentration and falsely increases potassium, lactate, protein, and other analytes. If a vein is not found quickly, the tourniquet should be released and reapplied later.

Question 27Specimen Collection and Processing

Which additive is contained in a lavender-stoppered evacuated blood collection tube?

  1. K2EDTA Correct answer.
  2. Sodium heparin
  3. Sodium citrate
  4. Potassium oxalate

Explanation

Lavender-stoppered tubes contain EDTA, which chelates calcium and prevents coagulation, making them suitable for hematology and blood bank testing. Heparin is found in green tubes, citrate in light blue tubes, and oxalate in gray tubes. Tube stopper color is a quick indicator of the additive present.

Question 28Specimen Collection and Processing

When should blood collection tubes be labeled with the patient's identifying information?

  1. Before entering the patient's room using the requisition
  2. In the laboratory just before analysis
  3. At the patient's side immediately after collection Correct answer.
  4. At the nursing station after all patients have been drawn

Explanation

Labeling at the bedside immediately after collection is required so the collector can verify the identity of the patient and the specimen at the same time. Pre-labeling tubes or labeling away from the patient creates a risk of misidentification. Unlabeled specimens are rejected and must be recollected.

Question 29Specimen Collection and Processing

Which urine specimen is preferred for a routine bacterial urine culture?

  1. A clean-catch midstream specimen Correct answer.
  2. The first-voided specimen of the day without cleansing
  3. A 24-hour pooled collection
  4. A specimen taken from an indwelling catheter from every patient

Explanation

A clean-catch midstream specimen minimizes contamination by flushing urethral flora, so it is the preferred routine specimen for urine culture. Catheterized specimens are reserved for patients who cannot provide a clean catch. Pooled 24-hour collections are not used for bacterial culture.

Question 30Specimen Collection and Processing

After applying the antiseptic to a venipuncture site for blood culture collection, the phlebotomist should:

  1. Proceed with the draw while the site is still wet
  2. Wipe off the excess antiseptic with an alcohol pad
  3. Fan the site with a hand to speed drying
  4. Allow the site to dry completely before venipuncture Correct answer.

Explanation

Antiseptics must be allowed to dry completely to achieve full antimicrobial effect; wiping or fanning defeats the disinfection process. Puncturing a wet site can drag residual organisms and antiseptic into the specimen. Air drying is the only acceptable method.

Question 31Specimen Collection and Processing

A patient has an intravenous line infusing in the right antecubital area. Where should the phlebotomist collect the blood specimen?

  1. From the IV catheter hub after discarding 5 mL
  2. From the right arm above the infusion site
  3. From the right arm using a tourniquet above the infusion site
  4. From the left arm, away from any infusion Correct answer.

Explanation

Blood should be drawn from the arm without an infusion because fluid and drug contamination dilute the specimen. Collecting above an infusing line is never acceptable. If no other site exists, collection distal to the IV site may be attempted with a documented note.

Question 32Specimen Collection and Processing

A venous blood specimen for lactic acid measurement should be:

  1. Collected in a serum separator tube and kept at room temperature
  2. Collected in a light blue citrate tube and refrigerated
  3. Collected in a plain red tube and protected from light
  4. Placed immediately in an ice-water slurry and transported to the laboratory Correct answer.

Explanation

Cells continue to metabolize glucose after collection, so chilling slows glycolysis and prevents falsely elevated lactate. The specimen should also be analyzed promptly. Serum separator tubes and light blue citrate tubes are not the appropriate containers for lactate testing.

Question 33Specimen Collection and Processing

Which collection tube is preferred for ABO/Rh typing and antibody screening?

  1. Green sodium heparin tube
  2. Lavender EDTA tube Correct answer.
  3. Light blue sodium citrate tube
  4. Gold serum separator tube

Explanation

EDTA prevents complement activation in vitro and preserves red cell antigens, making it the tube of choice for pretransfusion testing. Serum separators and heparin tubes can allow complement-mediated hemolysis that interferes with antibody detection. Blood bank tubes are often pink-topped but contain the same EDTA additive.

Question 34Specimen Collection and Processing

Which site is appropriate for a capillary puncture on a 3-day-old infant?

  1. The center of the heel pad
  2. The distal phalanx of the great toe
  3. The posterior curvature of the heel
  4. The medial or lateral plantar surface of the heel Correct answer.

Explanation

The medial and lateral plantar surfaces of the heel provide adequate tissue depth while avoiding the calcaneus. The center of the heel risks bone injury, and the posterior curvature is close to the Achilles tendon and prone to osteomyelitis. Toes and fingers are not used for capillary collection in young infants.

Question 35Specimen Collection and Processing

Which needle gauge is most appropriate for a routine venipuncture in an adult with normal veins?

  1. 23 gauge
  2. 21 gauge Correct answer.
  3. 25 gauge
  4. 27 gauge

Explanation

A 21-gauge needle provides adequate flow with minimal hemolysis and is the standard for routine adult venipuncture. Smaller gauges increase shear stress and hemolysis, while larger bores are reserved for donations or high-volume needs. The gauge number is inversely related to needle diameter.

Question 36Specimen Collection and Processing

When collecting a throat swab for group A streptococcus culture, the swab should be rubbed:

  1. Over the anterior dorsum of the tongue
  2. Over both tonsillar pillars and the posterior pharynx Correct answer.
  3. Along the gingival margin of the lower teeth
  4. Over the buccal mucosa on both sides

Explanation

The organism resides in the tonsillar crypts and posterior pharynx, so those areas must be sampled firmly. The tongue, cheeks, and gums harbor normal flora that contaminate the swab and obscure the pathogen. Contact with the teeth and uvula should also be avoided.

Question 37Specimen Collection and Processing

Which instruction should be given to a patient during an oral glucose tolerance test?

  1. Remain seated and refrain from smoking Correct answer.
  2. Walk briskly between blood collections
  3. Eat a light snack after the first blood draw
  4. Smoke only after the 2-hour specimen is collected

Explanation

Physical activity and smoking both alter glucose and insulin responses, so the patient should remain seated and avoid smoking for the duration of the test. Any food intake after the glucose load invalidates the results. Water is permitted, but other beverages are not.

Question 38Specimen Collection and Processing

A complete blood count performed on an EDTA specimen reports a platelet count of 40 × 10^9/L with platelet clumps seen on the blood film, but the patient has no bleeding and a normal platelet count one month earlier. What is the most appropriate next step?

  1. Recollect into a lithium heparin tube and report that count
  2. Report the EDTA result as the final value
  3. Proceed to a bone marrow aspiration
  4. Recollect in a citrate tube and correct for dilution Correct answer.

Explanation

Platelet clumping caused by EDTA-dependent antibodies produces a falsely low automated count, known as pseudothrombocytopenia. Recollection in citrate, with correction for the tube's dilution, usually gives the true count. Heparin can also cause platelet clumping and should not be used for this purpose.

Question 39Specimen Collection and Processing

Which finding confirms that a sweat chloride specimen is adequate for analysis?

  1. At least 75 mg of sweat collected in 30 minutes Correct answer.
  2. At least 5 mL of sweat collected in 1 hour
  3. Sweat collected from the forehead of the infant
  4. Any visible sweat on the gauze after 10 minutes

Explanation

A valid sweat test requires a minimum sweat weight of 75 mg collected over 30 minutes of pilocarpine iontophoresis. Insufficient sweat volume produces unreliable chloride values and must be reported as quantity not sufficient. Collection sites other than the forearm are not standard.

Question 40Specimen Collection and Processing

A semen specimen for routine analysis is collected at home. How should it be transported to the laboratory?

  1. Kept at room temperature and delivered within 6 hours
  2. Refrigerated at 4 °C and delivered within 24 hours
  3. Kept near body temperature and delivered within 1 hour Correct answer.
  4. Frozen and delivered on dry ice within 12 hours

Explanation

Sperm motility declines rapidly with cooling, so the specimen should be kept close to body temperature and delivered within 1 hour of collection. Refrigeration, freezing, and prolonged delay all invalidate motility assessment. The specimen is collected in a clean container free of lubricant or condom residue.

Question 41Hematology

What is the approximate circulating lifespan of a normal human red blood cell?

  1. About 10 days
  2. About 24 hours
  3. About 2 years
  4. About 120 days Correct answer.

Explanation

Red cells circulate for roughly 120 days before senescent membrane changes lead to their removal by macrophages in the spleen and liver. Production must therefore replace about 1% of the red cell mass daily.

Question 42Hematology

How does EDTA prevent coagulation in a hematology blood tube?

  1. It cross-links fibrinogen molecules
  2. It activates prothrombin to thrombin
  3. It blocks the action of antithrombin
  4. It chelates calcium ions Correct answer.

Explanation

EDTA is a chelating agent that binds divalent calcium, which is required at several steps of the coagulation cascade. Sequestration of calcium keeps the sample anticoagulated while preserving cell morphology for counting and smear review.

Question 43Hematology

Which hemoglobin species predominates in the red cells of a healthy adult?

  1. HbF
  2. HbA Correct answer.
  3. HbA2
  4. HbH

Explanation

Adult hemoglobin, HbA, consists of two alpha and two beta globin chains and makes up the large majority of hemoglobin after the first year of life. HbF and HbA2 are present only in small amounts in normal adults.

Question 44Hematology

Which platelet count range is typical for a healthy adult?

  1. 400 to 600 x 10^9/L
  2. 50 to 100 x 10^9/L
  3. 20 to 50 x 10^9/L
  4. 150 to 450 x 10^9/L Correct answer.

Explanation

The adult reference interval for platelet count is approximately 150 to 450 x 10^9/L. Counts below this range raise concern for bleeding risk and require review of the smear for clumping.

Question 45Hematology

The hematocrit reported on a complete blood count represents which quantity?

  1. The mean volume of an individual red cell
  2. The mass of hemoglobin per deciliter of blood
  3. The percentage of blood volume occupied by red cells Correct answer.
  4. The number of red cells per liter of blood

Explanation

Hematocrit, or packed cell volume, expresses the proportion of the whole blood sample taken up by erythrocytes. Analyzers derive it from the red cell count multiplied by the mean cell volume.

Question 46Hematology

Which area of a wedge blood smear is best suited for evaluating white cell morphology?

  1. The extreme tail, where cells are distorted
  2. The lateral margins, where platelets are most clumped
  3. The head, where cells are piled thickest
  4. The feathered edge, where cells form a single layer Correct answer.

Explanation

Optimal morphology is seen just behind the feathered edge, where red cells lie in a single layer without overlapping and leukocytes are flattened but intact. Thick areas obscure detail and the extreme tail distorts cell shape.

Question 47Hematology

What is the principal function of the neutrophil in peripheral blood?

  1. Histamine release in allergic reactions
  2. Antibody production
  3. Phagocytosis and intracellular killing of microbes Correct answer.
  4. Oxygen transport to tissues

Explanation

Neutrophils are the major circulating phagocytes; they migrate to sites of infection, ingest opsonized organisms, and kill them with granule enzymes and oxidative burst products. Their numbers rise rapidly in acute bacterial infection.

Question 48Hematology

A light blue–topped collection tube used in the hematology laboratory typically contains which additive, and for what purpose?

  1. EDTA, for routine hematology testing
  2. Heparin, for chemistry testing
  3. Sodium citrate, for coagulation testing Correct answer.
  4. Sodium fluoride, for glucose testing

Explanation

Light blue tubes contain a fixed concentration of buffered sodium citrate, which binds calcium and preserves labile coagulation factors. They are used for prothrombin time and activated partial thromboplastin time testing and must be filled to the marked volume.

Question 49Hematology

A patient with hemolytic anemia has a reticulocyte count of 15% (reference 0.5% to 2.5%). How should this result be interpreted?

  1. The bone marrow is failing to produce red cells
  2. The patient most likely has pure iron deficiency without blood loss
  3. The result is invalid because reticulocytes are not produced in hemolysis
  4. The bone marrow is responding appropriately to red cell loss Correct answer.

Explanation

Reticulocytes are newly released red cells, so a raised count shows the marrow is mounting an appropriate regenerative response to destruction or loss. A poor reticulocyte response in an anemic patient suggests marrow failure or nutritional deficiency instead.

Question 50Hematology

An elevated erythrocyte sedimentation rate is chiefly the result of which plasma change?

  1. Rouleaux formation promoted by fibrinogen Correct answer.
  2. Platelet clumping at the base of the tube
  3. A fall in plasma albumin concentration
  4. A rise in hematocrit above 60%

Explanation

Increased fibrinogen and other acute-phase globulins reduce the negative charge on red cells and encourage rouleaux, which sediment faster. The ESR is therefore a nonspecific marker of inflammation rather than a specific diagnostic test.