2
Performing
Ratio, Percent,
and Proportion
Calculations
Learning Objectives
1 Define ratios and describe their use in the pharmacy setting. (Section 2.1)
2 Utilize ratios to calculate medication doses or volumes. (Sections 2.1, 2.3)
3 Define percent as it pertains to pharmacy calculations. (Sections 2.2, 2.4)
4 Convert ratios to percents, percents to ratios, percents to decimals, and decimals to percents. (Sections 2.1, 2.2, 2.3)
5 Utilize percents to calculate medication doses or volumes. (Section 2.2)
For a key to the body system icons that appear in each chapter of this textbook, refer to the Preface.
6 Define proportion and the three ways it can be expressed in a pharmacy calculation. (Section 2.3)
7 Explain the rules and steps for using the ratioproportion method in pharmacy calculations. (Sections 2.1, 2.3)
8 Describe the applications and calculations associated with percentage of error and error tolerance. (Section 2.4)
ASHP/ACPE Accreditation Standards
To view the ASHP/ACPE Accreditation Standards addressed in this chapter, refer to Appendix D.
Whether you plan to practice in a community setting or an institutional setting, you will be required to perform calculations in your role as a pharmacy technician. This chapter introduces you to concepts that are fundamental to pharmacy calculations: ratios, percents, and proportions. Mastering ratios, percents, and proportions will allow you to complete a myriad of pharmacy calculations that are pertinent to the interpretation of prescriptions and medication orders, the conversions between measurement systems, and the computation of doses.