CSLB General Building (B) — All Questions

Which description of antecubital vein anatomy is correct?

• a.The basilic vein lies on the lateral or thumb side of the arm
• b.The cephalic vein lies laterally and the basilic vein medially, with the median cubital between them✓
• c.The median cubital vein lies deep to the brachial artery
• d.The cephalic vein lies on the medial or little finger side

In the antecubital fossa the cephalic vein runs along the lateral thumb side, the basilic vein along the medial little finger side, and the median cubital connects them across the middle. The median cubital is superficial and lies above, not beneath, the brachial artery. Reversing the cephalic and basilic positions would put the phlebotomist next to the artery and nerve without realizing it.

Which statement about arterial, venous and capillary blood is correct?

• a.Arterial blood is collected routinely for a CBC
• b.Venous blood is bright red because it carries nutrients
• c.Capillary blood is identical in composition to venous blood
• d.Arterial blood is bright red and oxygen rich, venous blood is darker, and capillary blood is a mixture of both plus interstitial fluid✓

Oxygenated arterial blood appears bright red, deoxygenated venous blood appears darker, and capillary blood collected by dermal puncture mixes arterial and venous blood with interstitial and intracellular fluid. Because of that mixture, capillary glucose tends to run higher and capillary potassium and total protein lower than venous values. Routine hematology and chemistry use venous blood; arterial puncture is reserved for blood gases and is outside the entry-level phlebotomy scope.

What distinguishes plasma from serum?

• a.Serum contains fibrinogen and plasma does not
• b.Plasma is obtained only from a serum separator tube
• c.Serum contains red cells and plasma does not
• d.Plasma contains fibrinogen and clotting factors, while serum is the fluid left after clotting✓

Plasma comes from an anticoagulated tube and still contains fibrinogen and the clotting factors, while serum is what remains after the blood has clotted and consumed fibrinogen. Neither fraction contains red cells once the specimen is centrifuged. Plasma requires an anticoagulant tube such as heparin or EDTA, not a serum separator tube.

After an EDTA tube is centrifuged, what is the thin layer between the plasma and the packed red cells?

• a.Fibrin clot
• b.Buffy coat, containing white blood cells and platelets✓
• c.Separator gel
• d.Hemolyzed plasma

The buffy coat is the pale layer of leukocytes and platelets that settles between the denser red cells and the lighter plasma. A fibrin clot forms only in a tube without anticoagulant, and separator gel exists only in gel tubes, not in a standard lavender tube. Hemolyzed plasma appears as pink or red discoloration throughout the plasma rather than as a discrete layer.

Which structural feature of veins is most relevant to venipuncture technique?

• a.Veins have thicker muscular walls than arteries
• b.Veins carry blood away from the heart
• c.Veins have one-way valves and thinner walls, so they collapse easily under strong vacuum✓
• d.Veins pulsate under the fingertip

Veins have thin walls and one-way valves that keep blood moving toward the heart, which is why a large vacuum tube or aggressive suction can collapse them and why needles are inserted pointing toward the heart away from valves. Arteries, not veins, have thick muscular walls and a palpable pulse. Arteries carry blood away from the heart while veins return it.

Which blood component makes up roughly 55 percent of whole blood volume?

• a.Plasma✓
• b.Erythrocytes
• c.Leukocytes
• d.Platelets

Plasma accounts for approximately 55 percent of whole blood and is about 90 percent water carrying proteins, electrolytes and waste products. Red cells make up most of the remaining 45 percent, which corresponds to the hematocrit. White cells and platelets together form only a small fraction, visible as the thin buffy coat after centrifugation.

A requisition is marked NPO. What does this abbreviation mean?

• a.The specimen is needed post-operatively
• b.Nothing by mouth✓
• c.No preservative ordered
• d.Notify provider only

NPO comes from the Latin nil per os and means the patient is to take nothing by mouth, a status the phlebotomist must respect by not offering food or fluids. It is distinct from a fasting order, though the two often overlap. Postoperative status, preservative choice and notification instructions are all conveyed by different notations.

In medical terminology, what does the suffix -emia indicate?

• a.Inflammation of a structure
• b.Surgical removal
• c.Excessive discharge or flow
• d.A condition of the blood✓

The suffix -emia refers to a blood condition, as in anemia, bacteremia and hyperkalemia. Inflammation is indicated by -itis, surgical removal by -ectomy, and excessive flow by -rrhea or -rrhage. Recognizing these roots helps a phlebotomist interpret test names and requisitions accurately.

A specimen is marked STAT. What does this require of the phlebotomist?

• a.Collect and deliver it immediately, ahead of routine work✓
• b.Collect it only after all fasting patients are done
• c.Collect it at the end of the shift and label the time
• d.Collect it with the next scheduled sweep

STAT means immediately, and these draws take priority over routine and timed collections so critical results reach the provider quickly. Deferring a STAT to a scheduled sweep or to the end of a shift defeats the purpose and can delay urgent treatment. Fasting patients are a scheduling convenience, not a higher priority than a STAT order.

Which tube and test pairing is correct?

• a.Lavender tube for a prothrombin time
• b.Light blue tube for a complete blood count
• c.Royal blue tube for trace element studies such as lead and zinc✓
• d.Gray tube for a type and crossmatch

Royal blue tubes are manufactured with low background metal contamination for trace element and toxicology testing. A CBC requires the lavender EDTA tube and a prothrombin time requires the light blue citrate tube, so those two pairings are reversed. Type and crossmatch is performed on a pink or red blood bank tube, never on a gray fluoride tube.