If the observed reticulocyte count is 6% and HCT is 30%, what is the calculated RPI?

To calculate the Reticulocyte Production Index (RPI), the formula involves the observed reticulocyte percentage and the hematocrit (HCT) value. The first step is to adjust the reticulocyte count based on the patient's hematocrit compared to a normal value, typically set at around 45% for adults.

The RPI is calculated using the following formula:

[ \text{RPI} = \left( \frac{\text{Reticulocyte Percentage}}{ \text{HCT (in decimal form)} / 45} \right) ]

Given the observed reticulocyte count of 6% and an HCT of 30%, the calculation becomes:

1. Convert the HCT to decimal: 30% translates to 0.30.

2. Calculate the correction factor: ( \frac{30}{45} = 0.6667 ).

3. Place the values into the formula:

[ \text{RPI} = \frac{6%}{0.6667} = 9% \text{ (or 0.09)} ]

This indicates a reticulocyte percentage of 9% compared to the adjusted norm. To convert this