Mastering 1 To 20 Dilutions in Hematology and Biochemistry

This video tutorial explains how to perform a 1:20 dilution, commonly used in hematology for manual WBC counts and in biochemistry when sample quantities are limited. The tutorial covers two methods: using 10 microliters and 20 microliters of sample, with detailed calculations for each. The importance of multiplying results by the dilution factor, rather than the sample quantity, is emphasized. Additional guidance is provided for using larger sample quantities, such as 30 or 40 microliters. The video aims to clarify the concept of 1:20 dilution and offers flexibility in method choice.

What is the primary use of a 1:20 dilution in hematology?

• To increase the concentration of a sample

• For manual WBC count when sample quantity is low

• To measure glucose levels

• For DNA sequencing

Why is it important to multiply the result by the dilution factor?

• To decrease the sample size

• To increase the sample size

• To obtain the actual concentration of the original sample

• To adjust for the reagent volume

In the first method, how much reagent is needed if 10 microliters of sample is used?

• 210 microliters

• 180 microliters

• 200 microliters

• 190 microliters

What is the total volume of the solution in the first method using 10 microliters of sample?

• 220 microliters

• 210 microliters

• 200 microliters

• 230 microliters

In the second method, how much reagent is needed if 20 microliters of sample is used?

• 390 microliters

• 380 microliters

• 370 microliters

• 360 microliters

What is the total volume of the solution in the second method using 20 microliters of sample?

• 420 microliters

• 430 microliters

• 410 microliters

• 400 microliters

If you have 30 microliters of sample, how much reagent is needed for a 1:20 dilution?

• 570 microliters

• 590 microliters

• 600 microliters

• 580 microliters

What is the total volume of the solution if 30 microliters of sample is used?

• 620 microliters

• 610 microliters

• 630 microliters

• 600 microliters

How do you calculate the amount of reagent needed for a 1:20 dilution?

• Multiply the sample volume by 19

• Multiply the sample volume by 20

• Divide the sample volume by 20

• Divide the sample volume by 19

What should you always remember to do with the result of a diluted sample?

• Divide it by the dilution factor

• Multiply it by the dilution factor

• Add the dilution factor

• Subtract the dilution factor