Lab worksheet #4: Hematocrit determination (Ch. 14 - Microhematocrit: p.179-180) Flashcards
What type of blood specimen is used for hematocrit determination?
Whole blood from EDTA
Which end of the microhematocrit or capillary tube should be used? (With or without colored ring)
Without colored ring
(T/F) The microhematocrit or capillary tube should only be 1/2 full with EDTA blood.
F (3/4 full)
(T/F) Capillary or microhematocrit tubes with blue bands contain anticoagulants.
F
(T/F) Capillary or microhematocrit tubes with red bands contain anticoagulants.
T
What type of capillary or microhematocrit tube should be used when the blood sample is anticoagulated with EDTA?
Capillary or microhematocrit tube with BLUE band
What type of capillary or microhematocrit tube should be used when the blood sample is obtained by skin puncture?
Capillary or microhematocrit tube with RED band
What anticoagulant is used in the capillary or microhematocrit tube with RED band?
Heparin
The dimensions of the usual capillary or microhematocrit tube are as follows:
___ mm long
___ mm inner bore size
75
1.2
How much blood can a capillary or microhematocrit tube contain?
Approximately 0.05mL of whole blood
(T/F) The presence of air bubbles inside the capillary or microhematocrit tube denotes poor skills and will affect the test results.
F
When sealing the capillary or microhematocrit tube with the sealing nonabsorbent clay, which end should be used?
The dry end with the colored ring
How long should be the length of the plug used to seal the capillary or microhematocrit tube?
Approximately 4mm
At what part of the microhematocrit centrifuge will you place the filled capillary tubes?
Radial grooves
The sealed end of the capillary or microhematocrit tube should be (away/near) the center of the microhematocrit centrifuge.
Away
Centrifuge the capillary or microhematocrit tubes between ___ and ___ g
10,000 - 15,000
According to Henry’s 22nd ed., centrifugation for ___ mins at ___ - ___ g is satisfactory unless the hematocrit exceeds 50%
5
10,000 - 12,000
According to Henry’s 22nd ed., when hematocrit exceeds 50%, centrifugation should be done for ___ mins. to ensure minimal plasma trapping.
10
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.
Trapped plasma
Increased amount of trapped plasma is seen in what conditions?
Sickle cell anemia Hypochromic anemia Spherocytosis Macrocytosis Thalassemia
After the centrifugation of the capillary or microhematocrit tubes, what is used to read the hematocrit?
Microhematocrit tube reader
The buffy coat includes the _____ and _____.
Platelets
Leukocytes
This is the red-gray layer between the RBCs and the plasma seen after centrifugation.
Buffy coat
This layer should not be included in the determination of the hematocrit.
Buffy coat
After centrifugation, what color would normal plasma exhibit?
Light yellow
After centrifugation, what color would suggest increased bilirubin?
Orange or green
After centrifugation, what color would suggest hemoglobinemia?
Ping or red
This is the condition wherein there is presence of free hemoglobin in the plasma.
Hemoglobinemia
This is the most common cause of hemolysis, which can lead to hemoglobinemia.
Poor technique
If the red cells are normocytic and normochromic, the _____ may be used in order to check the results of the hematocrit and the hemoglobin.
Rule of three
What is the formula for the “rule of three”?
HB X 3 = Hct +/- 3%
(T/F) The “rule of three” must not be utilized as a substitute for the actual laboratory determination of hematocrit or hemoglobin level.
T
What are the hematocrit reference ranges for the adult male? (Conventional units)
40 - 54 %
What are the hematocrit reference ranges for the adult female? (Conventional units)
35 - 49%
What are the hematocrit reference ranges for the adult male? (S.I. units)
0.40 - 0.54 (L/L)
What are the hematocrit reference ranges for the adult female? (S.I. units)
0.35 - 0.49 (L/L)
This is known as the volume of packed RBCs that occupies a given volume of whole blood.
Hematocrit
This is often referred to as the packed cell volume (PCV).
Hematocrit
This type of tube is recommended by the National Institute for Occupational Safety and Health to reduce the risk of capillary tube injuries.
Mylar-wrapped tubes
The values of duplicate hematocrits should agree within ___% (___ L/L)
1
0.01
Improper sealing of capillary tube causes a/an (increase/decrease) hematocrit reading as a result of blood loss during centrifugation.
Decrease
The improper sealing of capillary tube causes a decrease in hematocrit reading because of _____.
blood loss during centrifugation
A (higher/lower) number of erythrocytes are lost compared with plasma.
Higher
An increased concentration of anticoagulant (increases/decreases) the hematocrit reading as a result of erythrocyte shrinkage
Decreases
An increased concentration of anticoagulant decreases the hematocrit reading as a result of _____
Erythrocyte shrinkage
An increased or decreased result may occur if the specimen was not _____ and _____.
Mixed properly
The microhematocrit reader was not used properly
Insufficient centrifugation can (increase/decrease) hematocrit readings.
Increase
Delay in reading results after centrifugation can (increase/decrease) hematocrit readings.
Increase
Including the buffy coat of the specimen in the hematocrit reading can (increase/decrease) hematocrit readings.
Increase
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.
Higher
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.
1% to 3% (0.01 to 0.03 L/L)
(T/F) Automated instruments that calculate the hematocrit are unaffected by the trapped plasma.
T
A temporarily low hematocrit reading may result immediately after blood loss because plasma is replaced (faster/slower) than erythrocytes.
Faster
The fluid associated with dehydration causes a/an (increase/decrease) in plasma volume
Decrease
The fluid associated with dehydration falsely (increases/decreases) the hematocrit reading.
Increases
The introduction of interstitial fluid from a skin puncture can (increase/decrease) hematocrit reading.
Decrease
The improper flushing of a catheter can (increase/decrease) hematocrit reading.
Decrease
This type of centrifuge uses precalibrated capillary tubes and has built-in hematocrit scales, which eliminate the need for separate reading devices.
READACRIT centrifuge (Becton, Dickinson and Company, Franklin lakes, N.J.)
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.
SUREPREP Capillary tubes (Beckton Dickinson)