Centrifuge

Question 1

How does a centrifuge work?

Answer 1

Uses centrifugal force to separate substances of different densities that are in a solution

Question 2

What is the liquid portion of a centrifuged solution called?

Answer 2

supernatant

Question 3

what is the solid portion of a centrifuged solution called?

Answer 3

sediment (pellet)

Question 4

What is a centrifuge used for?

Answer 4

to separate blood, urine, and other bodily fluids

Question 5

What does the pellet consist of when you centrifuge blood?

What does the supernatant consist of when you centrifuge blood?

Answer 5

pellet —> cells

supernatant —> serum/plasma (depends on what type of blood tube is used)

Question 6

What does the pellet consist of you centrifuge urine? supernatant?

Answer 6

pellet: cells, crystals, debris
supernatant: liquid (discarded)

Question 7

what does the pellet consist of when bodily fluids are centrifuged?

Answer 7

pellet: cells, mucous, debris

Question 8

what are the two kinds of centrifuges?

Answer 8

1) clinical centrifuge

2) microhematocrit centrifuge

Question 9

what are the two kinds of clinical centrifuge?

Answer 9

1) horizontal or swing arm

2) angled (or fixed) head centrifuge

Question 10

what kind of centrifuge is a microhematocrit centrifuge?

Answer 10

angled (or fixed) head centrifuge

Question 11

What is a microhematocrit centrifuge? What does it do?

Answer 11

• will only accept microhematocrit tubes
• typically used to spin down blood for PCV + TS measurements
• the clay end of the microhematocrit tubes would point towards the outside of the centrifuge

Question 12

What is the setup of a horizontal head (swing arm) centrifuge?

Answer 12

• the tubes are movable

- they are vertical at rest then when it spins it will rise up to a horizontal position

Question 13

What are two disadvantages of the horizontal head (swing arm) centrifuge?

Answer 13

• excess speeds can cause heat buildup and damage delicate specimens (has increased friction which is due to increased movement which = heat buildup)
• some mixing of the supernatant + the pellet may occur when the specimen cup falls back into the vertical position

Question 14

How is an angle (fixed) head centrifuge set up?

Answer 14

-the arms where the tubes are placed are in a fixed (52 degree) angle

Question 15

what is the advantage of angled (fixed) head centrifuge?

Answer 15

it can rotate at higher speeds w/o excessive heat buildup because it uses less friction

Question 16

what are the general operations of a centrifuge?

Answer 16

• has an on/off switch
• tachometer (speed setting) - some don’t have this, some only have one speed setting
• braking device (used for emergency only) - used to rapidly stop the centrifuge; should ONLY be used in case of equipment malfunction
• MUST MUST MUST be counterbalanced!
• specimens should be spun at a specific time & specific speed

Question 17

What happens if the centrifuge is run too fast or too long?

Answer 17

It may rupture cells and destroy morphologic features

Question 18

What happens if the centrifuge runs too slow or for not enough time?

Answer 18

• it will not completely separate the specimen

- it will not concentrate the sediment