1. Puncturing the Skin to Obtain Capillary Blood
Health Science Technology II
Unit 18:3

2. Venipuncture When larger quantities of blood are needed
Blood is taken from the _________.

3. Cleanse the skin
70% isopropyl alcohol

4. Common puncture sites
Fingers
Heels (usually infants)
Earlobes

5. Finger Avoid thumb, index finger, pinkie
Avoid calluses, scars, rashes, sores, etc.
2-4 mm deep
Puncture should be made across the grain of lines

6. Heels
Use plantar & lateral aspects of heel
No deeper than 2 mm

7. Sterile Lancet

8. First drop of blood Always remove 1st drop with sterile gauze
Do not squeeze or milk out blood

9. After collection
Have patient hold sterile gauze over the site until bleeding stops
Stay with patient until bleeding stops

10. Performing a Microhematocrit
Unit 18:4

11. Hematocrit HCT, crit Packed Cell Volume, PCV
Measures the volume of RBCs as a percentage of blood
Normals:
Women: %
Men: %

12. Centrifuge
Spins blood at approximately revolutions per minute

13. Microhematocrit Capillary Tubes
Usually lined with an anticoagulant, such as heparin

14. Hold capillary tube at a slight angle to skin
Do not touch skin
Place end without indicator mark into the drop of blood
Allow blood to flow until it reaches mark

15. Seal Tube Hold gloved finger over the end of tube
Seal opposite end (end without blood) with sealing clay
Avoid contaminating clay block with blood

16. Spin the Tubes
Place capillary tube in centrifuge with clay seal against the rubber buffer
Usually spin tubes 3-5 minutes

17. Reading Line the top of the clay with zero
Read number at the top of the RBC layer

18. Measuring Hemoglobin
Unit 18:5

19. Hemoglobin (Hgb) Composed of 2 parts: Heme: contains iron
Globin: protein

20. Hemolysis Destruction of RBCs
Must be done in order to release hemoglobin from RBCs so it can be measured

21. Hemoglobinometer Measures the hemoglobin concentration in blood
Using color comparison, approximate reading is obtained
Relies on human eye for color match

22. Automated photometer Cuvette filled with hemolyzing solution
Color intensity measured automatically

23. Counting Blood Cells
Unit 18:6

24. Hemacytometer
Counting chamber in a calibrated slide with a grid for counting cells
9 large primary squares

25. Counting Leukocytes
Use 4 primary corner squares (contain 16 smaller squares
Only cells that touch the left line or top each of the large squares are counted

26. Leukocyte Formula
Add the numbers on the 4 corners on each side of the slide
Get an average of these 2 totals
Multiply the average by 50 (if 1:20 dilution)

27. Counting Erythrocytes
Center square is used
Center square is divided in to 25 secondary squares
Count in the 4 corner squares & center square of the secondary squares

28. Erythrocyte Formula
Obtain the average of the total count of the 5 squares on each side of the slide
Multiply by 10,000

29. Dilution of Sample Blood sample must be diluted
Different solutions are used to dilute for a WBC count vs. RBC count

30. Preparing & Staining a Blood Smear
Unit 18:7

31. Blood Smear
Differential count: 100 WBCs are counted, determine percentage of each type of WBC present
Examine form, structure & relative number of all types of blood cells

32. Stain Stain smear with Wright’s stain or 3 step quick stain
Examine smear at the feathered edge