Final answer:
If the aPTT is too long, the anticoagulant dosage should be increased. If the aPTT is too short, the anticoagulant dosage should be decreased.
Step-by-step explanation:
If the aPTT (clotting time) is too long, it indicates that the blood is taking longer to clot than it should. This suggests that there may be insufficient anticoagulant in the blood. In this case, the dosage of anticoagulant should be increased to bring the clotting time within the normal range.
On the other hand, if the aPTT is too short, it means that the blood is clotting too quickly. This may indicate an excessive amount of anticoagulant in the blood. To correct this, the dosage of anticoagulant should be decreased to achieve the desired clotting time.