Centrifuge Machine for Blood Grouping

[khalidm3]

Is it acceptable to use ordinary bench top centrifuge for blood Grouping by tube method at speed 1800-2000 rpm for 1 minute? May we calibrate the speed like serological centrifuge (Serofuge)? Minimum time in these machines is 1 minute.

[Mabel Adams]

You progably need to calculate the centrifugal force (g) being applied before deciding to use a non-serological centrifuge. Either the manual can tell you the force or I think there is a graphical tool for measuring the centrfuge head radius and calculating g forces. The reagent instructions sometimes tell you the g force necessary for the testing if I remember right. Once you know it runs at the proper g force, you can calibrate it for the right time to spin like usual. This is from memory so someone correct me if I am wrong.

[David Saikin]

As long as you validate it with an acceptable protocol you can use anything.

[rackman]

There are two ways that you can calculate this. 1. As Mabel stated above you need to calculate the g force that you need and then calculate the time or RPM that your centrifuge can do. or 2. (and this is the easy method) you can calculate the time based on speed or calculate the speed based on time, either way Gforce = Gforce. I choose this method because it was around before we knew about g force in centrifuges, and because I can remember it. So my first question is what are your defined constants? You state that the minimum time that your centrifuge can be set at is 1 minute. Can you adjust the speed lower than the 1800-2000 rpm? In either case your equation will look like this. (RPM1)(Time1) = (RPM2)(Time2).

Solving for Time:

(3500rpm)(15sec) = (1800rpm)(Xsec) =((3500)(15))/(1800) =29.16 seconds.

Solving for Speed:

(3500)(15) = (Xrpm)(60) =((3500)(15)/(60)) = 875 RPM

If you can set your centrifuge to 875 RPM then you are good to go, and as David states you'll have to validate. Good Luck.

[khalidm3]

Thanks for all of u