Answer to Question 1
ANS: C
The red count is lower than expected for the data; this suggests a cold agglutinin is present. The red cells are thus clumped at room temperature, and the clumps are being counted as one large cell. This lowers the red count and raises the MCV and MCHC. The only red cell parameter that is probably valid is the hemoglobin measurement.
Answer to Question 2
ANS: B
Sample age can have a profound effect on blood cell analysis. Specific problems with older samples include WBC fragility and loss, swelling (which increases the MCV) and possible lysis of RBCs, and the deterioration of platelets.