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Steps to Create a Shaded Field:
Prepare Your Data:

Add two new columns to your dataset: one for the "Low Limit" and one for the "High Limit."

Populate these columns with the respective values for the lower and upper limits for each data point.

Calculate the Shaded Area:

Add another column to calculate the difference between the upper and lower limits. This will represent the height of the shaded area.

Create a Stacked Area Chart:

Highlight the "Low Limit" and "Shaded Area" columns along with the dates.

Go to the "Chart Wizard" and select the "Area Chart" type.

Choose the "Stacked Area" subtype.

Format the Chart:

Once the chart is created, right-click on the area representing the "Low Limit" and set its fill color to "No Fill" to make it transparent.

Format the "Shaded Area" with your desired color to represent the range between the limits.

Overlay the Original Data:

Add your original data series (e.g., hemoglobin levels) to the chart by right-clicking and selecting "Source Data."

Ensure the original data is displayed as a line chart on top of the shaded area.

Adjust the Axes and Labels:

Format the axes and labels to ensure the chart is clear and easy to read.

This approach will give you a visually appealing shaded field between the upper and lower limits, replacing the lines.