02 LAB: HEMATOCRIT DETERMINATION & RULE OF THREE

Question 1

The volume of packed RBC that occupies a given volume of whole blood after centrifugation of a blood sample

Answer 1

Hematocrit

Question 2

In Adam’s microhematocrit method, the capillary tubes are filled up to ___ with blood

Answer 2

3/4

Question 3

In Henry’s microhematocrit method, the capillary tubes are filled up to ___ with blood

Answer 3

2/3

Question 4

Length of capillary tubes

Answer 4

7-7.5 cm

Question 5

Bore size of capillary tubes

Answer 5

1.2 mm

Question 6

A non-heparinized capillary tube has a ___ colored ring

Answer 6

blue

Question 7

A heparinized capillary tube has a ___ colored ring

Answer 7

red

Question 8

The capillary tube is placed into the tray with sealing compound at ___-degree angle

Answer 8

90

Question 9

The plug of the capillary tube should be atleast __ mm long

Answer 9

4

Question 10

In the microhematocrit centrifuge, the clay ends should face ___ from the center

Answer 10

away

Question 11

The capillary tube is centrifuged at ___ for ___

Answer 11

10 000 g - 15 000 g
4-5 mins

Question 12

Reference range of hematocrit for males

Answer 12

40-54%

Question 13

Reference range of hematocrit for females

Answer 13

35-49%

Question 14

T/F: the estimation of hemoglobin and RBC is possible on the bases of hct value under normal circumstances

Answer 14

T

Question 15

Under normal circumstances, 1% hct = ___ g/dL hgb or ___ RBC/cumm

Answer 15

0.34 g/dL
107 000 RBC/cumm

Question 16

The improper sealing of the capillary tube causes a ___ hematocrit reading as a result of ___ of blood during centrifugation

Answer 16

decreased
leakage

Question 17

An increased concentration of anticoagulant ___ the hematocrit reading

Answer 17

decreases

Question 18

A decreased or increased result may occur if the specimen was not ___ properly

Answer 18

mixed

Question 19

Insufficient centrifugation or a delay in reading results after centrifugation causes hematocrit readings to ___

Answer 19

increase

Question 20

The buffy coat of the specimen should not be included in the hematocrit reading because this falsely ___ the result

Answer 20

elevates

Question 21

Source of error:

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

Answer 21

trapped plasma

Question 22

Trapping of the plasma causes the microhematocrit to be ___ higher than the value obtained using automated instruments that calculate the hematocrit

Answer 22

1-3%

Question 23

How is hematocrit computed?

Answer 23

RBC X MCV

Question 24

A temporarily low hematocrit reading may result immediately after a ___ because plasma is replaced faster than are the RBCs

Answer 24

blood loss

Question 25

The fluid loss associated with dehydration causes a ___ in plasma volume and falsely ___ the hematocrit reading

Answer 25

decrease
increases

Question 26

The introduction of interstitial fluid from a skin puncture of the improper flushing of an IV catheter causes ___ hematocrit readings

Answer 26

decreased

Question 27

The length of the Wintrobe tube

Answer 27

11.5 cm

Question 28

Size of the bore of Wintrobe tube

Answer 28

3 mm

Question 29

Calibration of Wintrobe tube used for ESR

Answer 29

0-10 (red)

Question 30

Calibration of Wintrobe tube used for hematocrit

Answer 30

10-0 (white)

Question 31

The anticoagulant of choice in Wintrobe tube is ___

Answer 31

double oxalate

Question 32

In the Wintrobe method of hematocrit determination, the tube is centrifuged at ___ for ___

Answer 32

3 000 rpm
30 mins

Question 33

In the Wintrobe method of hematocrit determination, the hematocrit is computed by what formula?

Answer 33

height of packed RBC/ height of whole blood used

Question 34

The Haden’s modification of hematocrit determination uses ___ as anticoagulant

Answer 34

1.1 sodium citrate in distilled water

Question 35

The Haden’s modification of macrohematocrit method uses what formula to determine hematocrit concentration?

Answer 35

volume of packed RBC x 20

Question 36

In the Haden’s modification, if the blood used is less than 5 mL, the formula to use is ___

Answer 36

(volume of packed RBC/ volume of whole blood used) x 100

Question 37

In the Von Allen method of macrohematocrit method uses ___ as an anticoagulant of choice

Answer 37

1.6% sodium oxalata in distilled water

Question 38

This macrohematocrit method uses a tube with bulb and calibration of 1-10 cm (10-100 mm)

Answer 38

Von Allen Method

Question 39

In the Von Allen method, the capillary tube is centrifuged at ___ for ___

Answer 39

2 500 rpm
15-30 mins

Question 40

In the Sanford-Magath macrohematocrit method, the anticoagulant of choice is ___

Answer 40

1.3% sodium oxalate

Question 41

In the Sanford-Magath macrohematocrit method, the tube is calibrated at ___ per division

Answer 41

1 mm

Question 42

In the Sanford-Magath macrohematocrit method, the tube is about ___ long and a ___ mouth

Answer 42

5 inches
funnel-like

Question 43

In the Sanford-Magath macrohematocrit method, the tube is centrifuged at high speed for ___

Answer 43

15 mins

Question 44

In the Bray’s macrohematocrit method, the anticoagulant of choice is ___

Answer 44

heparin

Question 45

In the Bray’s macrohematocrit method, the tube should be ___-bottomed and calibrated on both sides, similar to ___ tube

Answer 45

flat
Wintrobe

Question 46

In the Bray’s macrohematocrit method, the calibration is ___, each division is ___, and the capacity is ___

Answer 46

10-50 mm
1 mm
5 mL

Question 47

In the Bray’s macrohematocrit method, the tube is left at a vertical position for ___

Answer 47

1 hour

Question 48

According to the rule of three, hemoglobin is computed as ___

Answer 48

RBC X 3

Question 49

According to the rule of three, hematocrit +/- 3 is computed as ___

Answer 49

hemoglobin x 3

Question 50

The rule of three only applies to specimens that have ___, ___ RBCs

Answer 50

normocytic
normochromic