Beckman Airfuge Ultracentrifuge
Principle
The tabletop Airfuge Ultracentrifuge is a miniature air turbine capable of accelerating rotors up to 110,000 rpm in only 30 seconds. The instrument uses no vacuum or high-speed bearings; the rotor is supported & turned by streams of air. The Airfuge Ultracentrifuge is an exceptionally safe instrument because the rotor is held in place by a pressure differential created during centrifugation. A special rotor (ACR-90) is used to clarify lipemic serum by flotation of the chylomicrons after 10 minutes of centrifugation. The aluminum base of the rotor is anodized for corrosion resistance. The base has turbine flutes which provide the driving surface for the jets of air that lift & turn the rotor. A white plastic bushing, fitted in the rotor bottom, aids rotor deceleration. The rotor stand supports the rotor when loading & unloading, & when securing the stainless steel rotor lid. Polyethylene liners fit into the cavity of the rotor base for carrying the sample. The small 2.4 mL liner uses a Delrin adapter to ensure a tight fit. Liners can be used only once. The liners are formed into two chambers & have a dome with a filling hole at the top. The inner & outer chambers are sealed from each other when the liner is compressed by the rotor lid. During acceleration of the rotor, fluid pressure develops & opens the seal. The lightest particles in the sample, the chylomicrons, then float into the inner chamber. During deceleration, the chambers are sealed again, & the chylous material is isolated in the inner chamber. The 3.5 mL liner yields about 2.6 mL of clarified serum, & the 2.4 mL liner yields about 1.4 mL.
Preparation
No special patient preparation is required.
Specimen
Serum is the preferred sample.
Interferences
The Beckman Airfuge Ultracentrifuge is used to delipify serum samples. Lipemic samples interfere with a number of constituents on the different chemistry analyzers, thus causing erroneous results. For this reason all lipemic samples should be spun down before reporting results. Triglyceride is the only constituent that should be reported on a lipemic sample.