Lab worksheet #4: Hematocrit determination (Ch. 14 - Microhematocrit: p.179-180)

Question 1

What type of blood specimen is used for hematocrit determination?

Answer 1

Whole blood from EDTA

Question 2

Which end of the microhematocrit or capillary tube should be used? (With or without colored ring)

Answer 2

Without colored ring

Question 3

(T/F) The microhematocrit or capillary tube should only be 1/2 full with EDTA blood.

Answer 3

F (3/4 full)

Question 4

(T/F) Capillary or microhematocrit tubes with blue bands contain anticoagulants.

Answer 4

F

Question 5

(T/F) Capillary or microhematocrit tubes with red bands contain anticoagulants.

Answer 5

T

Question 6

What type of capillary or microhematocrit tube should be used when the blood sample is anticoagulated with EDTA?

Answer 6

Capillary or microhematocrit tube with BLUE band

Question 7

What type of capillary or microhematocrit tube should be used when the blood sample is obtained by skin puncture?

Answer 7

Capillary or microhematocrit tube with RED band

Question 8

What anticoagulant is used in the capillary or microhematocrit tube with RED band?

Answer 8

Heparin

Question 9

The dimensions of the usual capillary or microhematocrit tube are as follows:
___ mm long
___ mm inner bore size

Answer 9

75

1.2

Question 10

How much blood can a capillary or microhematocrit tube contain?

Answer 10

Approximately 0.05mL of whole blood

Question 11

(T/F) The presence of air bubbles inside the capillary or microhematocrit tube denotes poor skills and will affect the test results.

Answer 11

F

Question 12

When sealing the capillary or microhematocrit tube with the sealing nonabsorbent clay, which end should be used?

Answer 12

The dry end with the colored ring

Question 13

How long should be the length of the plug used to seal the capillary or microhematocrit tube?

Answer 13

Approximately 4mm

Question 14

At what part of the microhematocrit centrifuge will you place the filled capillary tubes?

Answer 14

Radial grooves

Question 15

The sealed end of the capillary or microhematocrit tube should be (away/near) the center of the microhematocrit centrifuge.

Answer 15

Away

Question 16

Centrifuge the capillary or microhematocrit tubes between ___ and ___ g

Answer 16

10,000 - 15,000

Question 17

According to Henry’s 22nd ed., centrifugation for ___ mins at ___ - ___ g is satisfactory unless the hematocrit exceeds 50%

Answer 17

5

10,000 - 12,000

Question 18

According to Henry’s 22nd ed., when hematocrit exceeds 50%, centrifugation should be done for ___ mins. to ensure minimal plasma trapping.

Answer 18

10

Question 19

This is the term used to describe the minute amount of plasma that remains in the red blood cell portion even when the microhemtacorit tube was spun for the exact time period and at the proper speed.

Answer 19

Trapped plasma

Question 20

Increased amount of trapped plasma is seen in what conditions?

Answer 20

Sickle cell anemia
Hypochromic anemia
Spherocytosis
Macrocytosis
Thalassemia

Question 21

After the centrifugation of the capillary or microhematocrit tubes, what is used to read the hematocrit?

Answer 21

Microhematocrit tube reader

Question 22

The buffy coat includes the _____ and _____.

Answer 22

Platelets

Leukocytes

Question 23

This is the red-gray layer between the RBCs and the plasma seen after centrifugation.

Answer 23

Buffy coat

Question 24

This layer should not be included in the determination of the hematocrit.

Answer 24

Buffy coat

Question 25

After centrifugation, what color would normal plasma exhibit?

Answer 25

Light yellow

Question 26

After centrifugation, what color would suggest increased bilirubin?

Answer 26

Orange or green

Question 27

After centrifugation, what color would suggest hemoglobinemia?

Answer 27

Ping or red

Question 28

This is the condition wherein there is presence of free hemoglobin in the plasma.

Answer 28

Hemoglobinemia

Question 29

This is the most common cause of hemolysis, which can lead to hemoglobinemia.

Answer 29

Poor technique

Question 30

If the red cells are normocytic and normochromic, the _____ may be used in order to check the results of the hematocrit and the hemoglobin.

Answer 30

Rule of three

Question 31

What is the formula for the "rule of three"?

Answer 31

HB X 3 = Hct +/- 3%

Question 32

(T/F) The "rule of three" must not be utilized as a substitute for the actual laboratory determination of hematocrit or hemoglobin level.

Answer 32

T

Question 33

What are the hematocrit reference ranges for the adult male? (Conventional units)

Answer 33

40 - 54 %

Question 34

What are the hematocrit reference ranges for the adult female? (Conventional units)

Answer 34

35 - 49%

Question 35

What are the hematocrit reference ranges for the adult male? (S.I. units)

Answer 35

0.40 - 0.54 (L/L)

Question 36

What are the hematocrit reference ranges for the adult female? (S.I. units)

Answer 36

0.35 - 0.49 (L/L)

Question 37

This is known as the volume of packed RBCs that occupies a given volume of whole blood.

Answer 37

Hematocrit

Question 38

This is often referred to as the packed cell volume (PCV).

Answer 38

Hematocrit

Question 39

This type of tube is recommended by the National Institute for Occupational Safety and Health to reduce the risk of capillary tube injuries.

Answer 39

Mylar-wrapped tubes

Question 40

The values of duplicate hematocrits should agree within ___% (___ L/L)

Answer 40

1 | 0.01

Question 41

Improper sealing of capillary tube causes a/an (increase/decrease) hematocrit reading as a result of blood loss during centrifugation.

Answer 41

Decrease

Question 42

The improper sealing of capillary tube causes a decrease in hematocrit reading because of _____.

Answer 42

blood loss during centrifugation

Question 43

A (higher/lower) number of erythrocytes are lost compared with plasma.

Answer 43

Higher

Question 44

An increased concentration of anticoagulant (increases/decreases) the hematocrit reading as a result of erythrocyte shrinkage

Answer 44

Decreases

Question 45

An increased concentration of anticoagulant decreases the hematocrit reading as a result of _____

Answer 45

Erythrocyte shrinkage

Question 46

An increased or decreased result may occur if the specimen was not _____ and _____.

Answer 46

Mixed properly | The microhematocrit reader was not used properly

Question 47

Insufficient centrifugation can (increase/decrease) hematocrit readings.

Answer 47

Increase

Question 48

Delay in reading results after centrifugation can (increase/decrease) hematocrit readings.

Answer 48

Increase

Question 49

Including the buffy coat of the specimen in the hematocrit reading can (increase/decrease) hematocrit readings.

Answer 49

Increase

Question 50

The trapping of the plasma causes the microhematocrit to be 1% to 3% (0.01 to 0.03 L/L) (higher/lower) than the value obtained using automated instruments that calculate the hematocrit and are unaffected by the trapped plasma.

Answer 50

Higher

Question 51

The trapping of the plasma causes the microhematocrit to be ___% to ___% (___ to ___ L/L) higher than the value obtained using automated instruments that calculate the hematocrit and are unaffected by the trapped plasma.

Answer 51

1% to 3% (0.01 to 0.03 L/L)

Question 52

(T/F) Automated instruments that calculate the hematocrit are unaffected by the trapped plasma.

Answer 52

T

Question 53

A temporarily low hematocrit reading may result immediately after blood loss because plasma is replaced (faster/slower) than erythrocytes.

Answer 53

Faster

Question 54

The fluid associated with dehydration causes a/an (increase/decrease) in plasma volume

Answer 54

Decrease

Question 55

The fluid associated with dehydration falsely (increases/decreases) the hematocrit reading.

Answer 55

Increases

Question 56

The introduction of interstitial fluid from a skin puncture can (increase/decrease) hematocrit reading.

Answer 56

Decrease

Question 57

The improper flushing of a catheter can (increase/decrease) hematocrit reading.

Answer 57

Decrease

Question 58

This type of centrifuge uses precalibrated capillary tubes and has built-in hematocrit scales, which eliminate the need for separate reading devices.

Answer 58

READACRIT centrifuge (Becton, Dickinson and Company, Franklin lakes, N.J.)

Question 59

The use of this type of capillary tube eliminates the use of sealants. These have a factory-inserted plug that seals automatically when the blood touches the plug.

Answer 59

SUREPREP Capillary tubes (Beckton Dickinson)