Blood test results are usually graphed using line graphs, a visual representation of data that enables you to see how your results compare to a normal test. You may also be able to use the graph to predict future trends in your test levels. Line graphs compare two variables (pieces of data) and can be used to graph a wide variety of blood tests, including complete blood counts, vitamin levels, and glucose tolerance tests.

Draw a 10 inch horizontal line with your ruler. Make tic marks every inch. Label this line "time." Blood tests are sometimes taken in 30 minute or one hour intervals. Sometimes they can be used to track trends over weeks or months. Choose a label that best suits your test. For example, if you are graphing a 5-hour glucose tolerance test, label the graph "time(minutes)" or "time(hours)."

Label the tick marks on the horizontal axis (the line you just drew). For example, if you wrote "time(hours)," label the tic marks in one hour (1, 2, 3, 4, 5) or 30 minute (0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5) intervals.

## Sciencing Video Vault

Draw a vertical axis. At the far left corner, draw a straight line going up to an inch away from the top of the page. Label this line with your measured variable. For example, if a glucose tolerance test is measuring blood glucose (mM), then label that line "blood glucose (mM)."

Place tick marks on the vertical line every inch. Label with the appropriate measurement. For example, glucose levels might be measured in increments of 4mM, so label the tick marks 4, 8, 12, 16, 20. Values should start at the bottom and increase as they go up.

Plot your data. Take the first data set and make a point on your graph where the two lines intersect. For example, if the first reading is 5mM at 0 minutes, draw a line straight upward from 0, and a line straight across from 5mM. Make a point on the graph where the two lines intersect. Drawing actual lines is optional: your graph will look neater if you draw imaginary lines with your finger.

Repeat step five for all data points.

Connect all data points with a single line going from the left (at the vertical axis) to the last data point on the right.