Final answer:
A CBC specimen is clotted because the blood was not mixed sufficiently with the anticoagulant, leading to natural clotting. Proper mixing is crucial for accurate CBC results and to avoid the need for redrawing the specimen.
Step-by-step explanation:
A CBC specimen is clotted and needs to be redrawn. The clotting is most likely caused because the blood and anticoagulant were not mixed sufficiently in the tube. When a blood sample is collected for a Complete Blood Count (CBC), it is essential to mix it adequately with the anticoagulant to prevent the clotting process. Anticoagulants like EDTA or lithium heparin are used in collection tubes to chelate calcium ions and inhibit the coagulation cascade, preventing clot formation. If the blood is not mixed well with the anticoagulant post-collection, the natural clotting process, involving the conversion of fibrinogen to fibrin by thrombin, can ensue, leading to a clotted specimen that is unsuitable for analysis and requires redrawing.
The prevention of clotting inside the collection tube allows for accurate measurement of hematological parameters, such as the count of red blood cells, white blood cells, and platelets, as well as the determination of hemoglobin concentration and hematocrit levels. Inadequate mixing can be attributed to several factors such as insufficient inversion of the tube after collection or a delay in the mixing process. Proper technique is critical to ensure the quality and reliability of CBC results.