Hematocrit hema Flashcards

1
Q

Volume of packed red blood cells that occupies a given volume of
whole blood after centrifugation of a blood sample
Also known as ____ or ____
Reported either as ___,___,___,___

A

Hematocrit
- Packed Cell Volume (PCV) or Erythrocyte Volume Fraction (EVF)
-percentage(%), cell volume percent (CV%), volume percent (Vol%) or in liters per liter (L/L)

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2
Q

Plasma

A

water, nutrients proteins hormones

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3
Q

Buffy coat

A

wbc, platelets

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4
Q

Hematocrit

A

RBC

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5
Q

Normal blood

A

37-47% hct female
42-52% hct male

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6
Q

depressed hct %

A

Anemia

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7
Q

elevated hct %

A

Polycythemia

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8
Q

HEMATOCRIT
DETERMINATION

A

Macro method ( Wintrobe method) & micro method (Adam’s Microhematocrit)

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9
Q

Adam’s Microhematocrit method
Procedure:
1. Fill two plain capillary tubes approximately three-quarters (3/4) full with blood anticoagulated with ___
> 2/3 filled, ____, filled portion ___
Length:___
Bore: ___
____ - for blood collected on anticoagulated tube
____ - for blood from skin puncture

A
  • EDTA/heparin
    -0.05 ml blood
  • 5 cm
  • 7-7.5 cm
  • 1.2 mm
  • Non-heparinized (blue ring) capillary tube
  • Heparinized (red ring) capillary tube
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10
Q

Seal the end of the tube with the colored ring using___
> Seal by placing the dry end into the tray with sealing compound at a __.
> Rotate the tube slightly and remove it from the tray
> The plug should be at least___ long

A

nonabsorbent sealing clay
90-degree angle
4 mm

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11
Q

Balance the tubes in a
microhematocrit centrifuge with the clay ends facing ___ , touching the rubber gasket

A

outside away from the center

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12
Q

Tighten the head cover on the
centrifuge and close the top. Centrifuge the tubes at ___ for ___.

A

10,000g to 15,000 g for 4-5 minutes

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13
Q

Determine the hematocrit by using a ___

A

microhematocrit reading device

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14
Q

The values of duplicate hematocrits
should agree within ___

A

1% (0.1 L/L)

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15
Q

HCT Reference Values
Conventional Unit:

A

Male: 40-54%
Female: 35-49%

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16
Q

HCT Reference Values
SI Unit:

A

Male: 0.40-0.54 L/L
Female: 0.35-0.49 L/L

17
Q

Estimation of __ and ___ is possible on the basis of the hematocrit value under normal circumstances.
1% hematocrit - ___ Hemoglobin or ___ RBC/cumm

A

hemoglobin and red blood cell count
- 0.34 g/dL
- 107,000

18
Q

INCREASED HCT

A
  1. the specimen was not mixed properly
  2. Insufficient centrifugation or a delay in reading results after
    centrifugation
  3. The buffy coat of the specimen should not be included in the hematocrit reading because this falsely elevates the result
  4. microhematocrit reader is
    not used properly
  5. The fluid loss associated with dehydration causes a decrease in plasma volume and falsely increases the hematocrit reading
19
Q

DECREASED HCT

A
  1. Improper sealing of the capillary tube as a result of leakage of blood during centrifugation
  2. An increased concentration of anticoagulant (short draw in an
    evacuated tube)
  3. the specimen was not mixed properly
  4. microhematocrit reader is
    not used properly
  5. A temporarily low hematocrit reading may result immediately after a blood loss because plasma is replaced faster than are the RBCs
  6. Proper specimen collection is an important consideration. The
    introduction of interstitial fluid from a skin puncture or the improper flushing of an intravenous catheter causes decreased hematocrit readings
20
Q

Many disorders, such as __,__,__,__,__,___ may cause plasma to be trapped in the RBC layer even if the procedure is performed properly

A

sickle cell anemia, macrocytic anemias, hypochromic
anemias, spherocytosis, and thalassemia,

21
Q

____: amount of plasma that still remains in the RBC portion after the microhematocrit has been spun.

A

Trapped Plasma

22
Q

Trapping of the plasma causes the microhematocrit to be ___ to ____ higher than the value obtained using automated instruments that calculate the hematocrit and are unaffected by the trapped plasma

A

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

23
Q

Automated Methods
1
2

A

( Coulter Counter, Autoanalyzer)

24
Q

Hematocrit = __

A

RBC x MCV

25
Q

This method utilizes the Wintrobe
tube
Length:___
Bore: ___
Has 2 calibrations
0-10 (Red) is used for ___
10-0 (White) used for __
Anticoagulant of choice: __

A

Wintrobe Method
11.5 cm
3 mm
Erythrocyte Sedimentation Rate (ESR)
hematocrit
Double oxalate

26
Q

Procedure
1. Fill the Wintrobe tube with blood using a Pasteur pipette
2. Centrifuge the tube at___
3.Read the volume of packed red blood cells
4.Compute for the hematocrit level using the formula: ____

A

Wintrobe Method
3000 rpm for 30 minutes
Hematocrit = (height of packed RBC / height of whole blood used) x 100

27
Q

Rule of Three
> This rule only applies to specimens that have __,___

A

RBC x 3 = Hgb
Hgb x 3 = Hct +/-3
- normocytic normochromic
RBCs