According to USP criteria, which statement about MAA preparations is correct?

The correct statement regarding MAA (macroaggregated albumin) preparations according to USP criteria emphasizes that up to 10% of the particles in the preparation may exceed 150 micrometers in diameter. This is significant because MAA particles are utilized in lung perfusion imaging, and their size is crucial for ensuring the particles are distributed appropriately within the pulmonary circulation.

The rationale behind this acceptable size limit is that while most particles should be within a certain range to avoid lodging in the smaller capillaries, a small percentage of slightly larger particles can be tolerated. This helps balance the need for effective imaging outcomes while recognizing the inherent variability in the preparation process.

Other statements either misrepresent the size criteria or do not align with clinical practice requirements. For instance, while the ideal size for effective imaging purposes is constrained, the complete absence of any particles exceeding given specifications is not practical in actual preparations. Thus, maintaining a controlled range with specific allowances is important for patient safety and diagnostic accuracy.