# Mathematic Calculations and Applications for the Histology Laboratory

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While many changes have occurred in recent years, increased automation in the modern histology laboratory has not diminished the need for mathematical calculations and applications. Immunohistochemical (IHC) staining has become a more routine aspect of the histology workload and challenges personnel to understand and troubleshoot the variables inherent in the preparation and staining process. This course is intended to provide a review of the basic math applications frequently used in the histology laboratory, to provide an opportunity to practice pertinent calculations in preparation for the national certification examination and/or as a refresher for continuing education purposes.

### Continuing Education Credits

- P.A.C.E.® Contact Hours: 1.5 hour(s)
- Florida Board of Clinical Laboratory Science CE Credit Hours -

General (Histology): 1.5 hour(s)

### Objectives

- Define terms associated with basic histology math processes.
- Apply unit conversions within the metric system, including the use of ratio and proportion.
- Covert temperatures between the Fahrenheit and Celsius systems.
- Calculate accurate concentrations of solutions, including molar concentrations, normal concentrations, percent concentrations, and conversions between percent and molar solutions.
- Perform dilution calculations to prepare working solutions from concentrated solutions.
- Determine the gravimetric factor in staining solution preparation and calculate the amount of dye needed in preparation of new stains.

### Course Outline

- Introduction to Basic Laboratory Math
- Why do I Need to Understand the Math?
- Basic Math Applications in the Histology Laboratory
- The Metric System
- What is the Metric System?
- Conversion Within the Metric System
- Use of Ratio and Proportion
- Unit Conversion
- Convert 4 g/L to mg/L.
- Express 6.5 mL in liters.
- Convert 378 mg/dL to g/L.Hint! There are 2 conversions needed here.
- Making Temperature Conversions
- Conversion Between Fahrenheit and Celsius Scales
- Convert 50 degrees Celsius to degrees Fahrenheit.
- How many degrees Celsius is a temperature of -5 degrees Fahrenheit?
- Calculating Solution Concentrations
- Defining Solutions
- Percentage Solutions
- What is a Percentage Solution?
- Calculating Percent Weight/Volume (% w/v)
- Calculating Percent Volume/Volume (% v/v)
- Calculating Solute Amounts for Percent Solutions
- In preparation for an ATPase stain to differentiate muscle fiber types, a histology student needs to prepare a 1% solution of calcium chloride (CaCl2)...
- A histotechnologist, in preparing alcian blue dye to stain for acid mucopolysaccharides, realizes there is little more than a gram of dye left in the ...
- 15 mL of ammonium hydroxide is diluted to 2.0 L with distilled water. What percentage solution would that be?
- Working Solutions
- Stock Solution Dilutions
- A histologist has 75% alcohol ready for use, but needs 30% alcohol for the procedure she wants to perform. How many mL of the 75% solution will she ne...
- Molar Solutions
- What is a Molar Solution?
- The histotechnician needs to prepare a 1M solution of sodium acetate (C2H3NaO2). A liter of solution is needed. How much sodium acetate is needed to p...
- The histotechnician in the previous question misread the concentration of sodium acetate she needs for her special stain. She needs to prepare only 50...
- How many grams of NaOH (GMW = 40) are needed to prepare 750 mL of a 0.5M solution ?
- Interchanging Between Percent Concentration and Molarity
- The histotechnician, needing a 2M solution of sulfuric acid (H2SO4), finds a 10% solution of H2SO4 on the shelf.Calculate the molarity of the 10% solu...
- Normality
- What is a Normal Solution?
- A histologist is prepping a stock solution of 2N KCl. How many grams of KCl will he need to make 500 mL of this solution?(K = 39.10 g; Cl = 35.45 g) V...
- How will a histotechnician prepare 300 mL of 0.4N H2SO4 for his special stains?
- How many grams of KOH must be weighed out to prepare 400 mL of a 0.5N solution? (K = 39.10; 0 = 16; H = 1)
- Interchanging of Molarity and Normality Concentrations
- Given a 2N solution of CaCl2, convert the solution expression to molarity. (valence of CaCl2 = 2)
- Determining the Gravimetric Factor for Stains
- What is the Gravimetric Factor?
- The histotechnician needs to prepare 150 mL of a 3% solution of aniline blue. She realizes the old stock dye is depleted and she will need to open a n...
- References
- References

### Additional Information

**Level of instruction**: Basic

**Intended audience**: This course is appropriate for working histology professionals and for students in histology programs who want a review of basic math applications pertinent to the histology laboratory.

**Author information**: Carol Becker, MS, MLS(ASCP)

^{CM }is a retired Program Director for the Clinical Laboratory Science program and Histology program at OSF St. Francis Medical Center located in Peoria, Illinois. Carol received her Master's degree at the University of St. Francis in Joliet, Illinois and her Bachelor's degree in Medical Laboratory Science from the University of Illinois.

**Reviewer information**: Judith Thompson, BS, HTL(ASCP), is a retired histology department manager from OSF Saint Francis Medical Center located in Peoria, Illinois. She also served as Education Coordinator for the OSF St. Francis Histology program. Previous positions include serving as Program Director and Pathology Manager for Christiana Care Hospital/Delaware Community College, Newark, Delaware and Program Director/Pathology Manager/Assistant Director for Takeda-Abbott research project at Allegheny University Hospitals, Philadelphia, Pennsylvania.

**Course description**: While many changes have occurred in recent years, increased automation in the modern histology laboratory has not diminished the need for mathematical calculations and applications. Immunohistochemical (IHC) staining has become a more routine aspect of the histology workload and challenges personnel to understand and troubleshoot the variables inherent in the preparation and staining process. This course is intended to provide a review of the basic math applications frequently used in the histology laboratory, to provide an opportunity to practice pertinent calculations in preparation for the national certification examination and/or as a refresher for continuing education purposes.