Sample labelling

Clear labelling of the samples is essential for further processing in the laboratory. This includes fully completed consignment notes and clear labelling of the sample materials. Please contact our laboratories directly if you have any specific queries or need to send samples urgently.

Centrifugation

Many laboratory tests require the liquid part of the blood, serum or plasma. These samples therefore need to be centrifuged after blood collection. The spinning generates multiple g-forces, causing the liquid and solid components to separate.

Correct centrifugation

What does “correct centrifugation” mean?

  • The aim is to centrifuge as intensely as necessary and as gently as possible. If centrifugation is too strong, the sample may be damaged (change in the cells, haemolysis); if centrifugation is not sufficiently intense, cells may remain in the supernatant and interfere with the test results.  

Which type of centrifuge do I have to use?

  • There are two different types of centrifuge: fixed-angle centrifuges and swing-out rotor centrifuges. Only swing-out rotors are recommended for use with gel tubes.

 

Adjusting the centrifuge

It is important in this context to distinguish between revolutions per minute (rpm) and g-forces. G-force is the value that is important in order to obtain a good centrifugation result. The g-force setting is therefore particularly important when adjusting the centrifuge. The g-force required depends on the type of sample and tube.

How do I set the number of revolutions of my centrifuge correctly?

  • The number of revolutions denotes the number of times the rotor turns per minute, abbreviated to rpm (revolutions per minute). The required g-force has to be converted to the number of revolutions per minute (rpm) of the centrifuge. For this you may refer to the operating instructions of the centrifuge or calculate the revolutions per minute as indicated below:
  • The radius may for instance be marked on the rotor. The radius is reduced if reduction sleeves are used for smaller tubes.

The number of revolutions is also simple to calculate with the aid of a centrifugation calculator.

What happens during centrifugation?

Because of their greater specific weight, the cells sink to the bottom of the tube due to gravity, as also occurs with “sedimentation” (blood sedimentation rate). Centrifugation increases gravitational forces by a hundred to a thousand times, which leads to separation within a few minutes.

Measuring the radius correctly

Fixed-angle rotor

[Translate to EN:] Festwinkelrotor

Swing-out rotor

[Translate to EN:] Ausschwingrotor

Centrifugation conditions in different blood collection systems

Becton Dickinson
BD product nameCap colourCentrifugation conditions 
(Standard recommendation at 18–25 °C)
BD Vacutainer® Tubered1.300–2000 g for10 min
BD Vacutainer® SST™ II Advance Tubegold≤ 1.300 g for10 min 
BD Vacutainer® EDTA-Tubepurpleno centrifugation
BD Vacutainer® Citrat Tubelight blue150–200 g for 5 minutes (platelet-rich plasma)
2,000–2,500 g for 10 to 15 minutes (platelet-poor plasma)
> 3,000 g for 15 to 30 minutes (platelet-free plasma)
BD Vacutainer® Heparin Tubegreen≤ 1.300 g for 10 min 
BD Vacutainer® Tube for Glucose and Lactate Determination

grey≤ 1.300 g for 10 min 
BD Vacutainer® for  Homocysteine Determinationgrau≤ 1.300 g for 10 min 
BD Vacutainer® Tube
for Trace Element Determination
dark blue≤ 1.300 g for 10 min          
Sarstedt
BD product name Cap colourCentrifugation conditions 
(Standard recommendation at 18–25 °C)
S-Monovette® Serumwhite2.000 g for 10 min 
S-Monovette® Serum-Gelbrown2.500 g for 10 min
(use only swing-out-rotors)                 
S-Monovette® Haematologyred2.500 g for 10 min
S-Monovette® Coagulationgreen1.800 g for10 min
S-Monovette® Plasma     orange2.000 g for10 min
S-Monovette® Glucose     yellow2.000 g for10 min
S-Monovette® GlucoEXACT     grey2.000 g for 10 min
S-Monovette® ThromboExactredno centrifugation
S-Monovette® for PFA 100turquoiseno centrifugation
S-Monovette® Homocystein Z-Gelgreyno centrifugation
S-Monovette® for Metal Analysis                   orange no centrifugation