🩺 Nursing Question of the Day
Challenge yourself with one exam-style nursing question every day.
✅ Think carefully • ✅ Choose your answer • ✅ Then scroll down to check the explanation.
📝 Today’s Question:
Q: Which plasma expander can interfere with blood cross-matching due to its effect on erythrocyte aggregation?
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Dextran and Interference With Blood Cross-Matching
🩸 Why is Dextran the correct answer?
Dextran is a synthetic polysaccharide used as a plasma volume expander. It helps increase the volume of fluid circulating inside the blood vessels.
One important property of dextran is its effect on the behavior of erythrocytes, or red blood cells. It can promote erythrocyte aggregation, meaning that red blood cells tend to come together in aggregates.
This altered red-cell behavior can interfere with certain blood-bank tests, including blood grouping and cross-matching. Therefore, dextran is the classic answer when the question specifically links a plasma expander with erythrocyte aggregation and difficulty in compatibility testing.
🔬 Meaning and Origin of Important Medical Terms
Plasma: The pale-yellow liquid portion of blood. It carries blood cells, proteins, electrolytes, hormones, nutrients, and waste products.
Plasma expander: A fluid given intravenously to increase the circulating blood volume. It is particularly useful when the vascular volume needs to be supported.
Dextran: A glucose-based polysaccharide produced by certain microorganisms. The name is associated with dextro-, referring to the rightward optical rotation of certain sugars.
Erythrocyte: The medical term for a red blood cell. Erythro- comes from the Greek word erythros, meaning red, while -cyte comes from Greek kytos, meaning cell.
Aggregation: The process in which individual cells or particles come together to form a group or cluster. In this context, it refers to red blood cells coming together.
Cross-matching: A laboratory procedure used before a blood transfusion to check whether donor red blood cells are compatible with the recipient’s blood.
🧪 How Does Dextran Affect Cross-Matching?
Blood-bank testing depends on observing how red blood cells behave when exposed to specific antibodies. If the cells aggregate because of the presence of dextran, their appearance during testing may be altered.
This can make interpretation of compatibility tests more difficult. For this reason, the use of dextran is an important piece of information when blood grouping or cross-matching is being performed.
❌ Why Are the Other Options Incorrect?
Albumin is a naturally occurring plasma protein that contributes significantly to plasma oncotic pressure. Albumin solutions can be used for volume expansion, but the classic association with erythrocyte aggregation interfering with cross-matching is dextran.
Dextran is a plasma expander associated with erythrocyte aggregation and interference with blood-grouping and compatibility testing.
Hydroxyethyl starch is a synthetic colloid used for plasma-volume expansion. It is not the classic answer to the specific association described in this question.
Gelatin-based solutions are also colloid volume expanders. However, the characteristic association in this question is erythrocyte aggregation affecting cross-matching, which points to dextran.
👩⚕️ Important Nursing Points
- Know the patient’s recent IV fluids and plasma expanders before transfusion testing.
- Document administration of dextran accurately.
- Inform the appropriate laboratory or blood-bank personnel when relevant.
- Remember that interference with testing does not automatically mean that donor blood is incompatible.
DEXTRAN → red cells “stick” together.
Think: Dextran = aggregation = cross-match interference.
The combination of plasma expander + erythrocyte aggregation + cross-matching interference strongly points to Dextran.
Concept clarity • Easy recall • Nursing success
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