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Please check out our Tabletop Centrifuge section for more information or to find manufacturers that sell these products
No matter how elementary or advanced, every clinical laboratory has one essential device—a centrifuge. Whether it stands on the benchtop or floor and is refrigerated or not, a laboratory centrifuge fractionates liquid specimens by creating spin-induced high g-forces, and has long been a standard tool for both clinical and research applications. With broad utility, laboratory centrifuges are true workhorses, usually providing trouble-free service for many thousands of cycles over many years of steady use.
Benchtop, also known as tabletop, centrifuges have smaller throughputs and cannot provide high-end g-forces compared with floor models, but can accommodate most applications. Tabletop models include low-speed clinical centrifuges used for diagnostics; high-speed instruments for whole-cell harvesting and some nucleic acid applications; multipurpose centrifuges that accept either fixed-arm or swinging bucket rotors; and cell washers, which are highly specialized for washing red blood cells. For those considering a replacement or initial purchase, here is a brief overview of several of the most popular benchtop models used in the small laboratory. All are manufactured by laboratory equipment companies with long-standing reputations for quality and reliability.
Low-Speed, Fixed-Angle Clinical Centrifuge Options
At the entry point of its centrifuge line, the Drucker Company (Philipsburg, PA) produces the Model 614B as its most affordable basic centrifuge. The device is designed for the small lab or doctor’s office and is a single-speed centrifuge (up to 3150 rpm) used for blood separations. The 45º rotor will hold six test tubes of up to 15 mL (17 mm × 125 mm). The unit has a lid safety switch and is UL/CSA compliant. It includes a 30-minute timer, a double-encased, brushless motor, and a clear lid with a safety switch. The motor housing and rotation chamber are designed to allow for cool operation. Standard accessories include three sets of tube holders to fit tubes of varying lengths.
Thermo Fisher Scientific, Inc. (Waltham, MA) characterizes its Medilite centrifuge as ideal for routine low-speed centrifugation of blood and urine samples. Each Medilite centrifuge includes a 6- or 12-place 45º rotor and standard shields for aerosol containment. The device is designed with an integral 30-minute timer and accepts a variety of tube sizes up to 10 or 15 mL, depending on the rotor. This centrifuge also features a maintenance-free brushless motor, incorporates a power interrupter for user safety, and provides fixed speeds of 3100 or 2700 rpm.
BD Diagnostics (Sparks, MD) offers the ADAMS™ Compact II Centrifuge, which is designed for the doctor’s office or small lab. The fixed-angle rotor on this device accommodates 2–15 mL tubes and operates at a single speed of approximately 3200 rpm. This unit has a durable attached cover with safety interlock switch and stainless steel seals that minimize aerosol emissions. Accessory adaptors that come with the centrifuge accommodate a variety of tubes, including Vacutainer® tubes with Hemogard™ closures. Its 30-minute timer includes a Hold position for continuous operation. The brushless motor and housing design minimize temperature increases during operation.
Kendro Laboratory Products (Asheville, NC) produces the Primo™ model as part of its extensive Sorvall line of centrifuges. This centrifuge offers great flexibility and is ideal for clinical, molecular biology, and small medical laboratories. It can function as a micro-centrifuge, high-speed, and general-purpose centrifuge. The refrigerated Primo R model is also available. Both devices accommodate a wide choice of rotors (fixed-angle, swinging bucket, and microliter) and adapters for tubes from 0.2 to 100 mL, and produce speeds of 300 to 15,000 rpm. The instruments include an automatic rotor recognition system and electronic imbalance protection. The Highconic® 6 × 50 mL fixed-angle rotor allows the centrifugation of conical cell culture vessels at up to 10,000 × g, while a high-performance 24-place microliter rotor rapidly accelerates 1.5 or 2 mL tubes to a maximum RCF of 21,885 × g. Both rotors are autoclavable to 121 °C. An EASYcontrol™ II user panel displays all operational and run parameters. There are two acceleration and nine braking curves available for sensitive samples.
Eppendorf North America (Hauppauge, NY) offers its new cross-over micro-centrifuge models 5430 and 5430R (the refrigerated version). These centrifuges have speeds up to 30,130 × g (17,500 rpm) and accommodate 8 different rotors, providing options for spinning Eppendorf tubes, PCR strips, microplates, and 15 to 50 mL conical tubes. Additional features include automatic rotor recognition and imbalance detection, and patented compressor control for reduced energy consumption by the refrigerated model.
The Sartorius Group (Goettingen, Germany) makes universal centrifuges for sedimentation in swinging bucket and fixed-angle rotors. They are available as refrigerated or nonrefrigerated models, feature an imbalance switch, brushless- or induction-drive motors, and soft-start/soft-stop modes. The models have speeds that range from 100 up to 30,000 rpm, and have different adapters available for the same bucket, so that that same device can spin micro-centrifuge tubes to 250-mL vessels.
Conclusion
Whichever specific set of centrifuge features a clinician or investigator requires is likely available from the vast array of these devices now on the market. This seemingly mundane machine has grown increasingly complex in order to accommodate the higher speeds and more precise control needed for molecular and genetic applications. The basic models serve most clinical needs, however, and are well built, affordable, and highly dependable, assuring many years of service.
Please check out our Tabletop Centrifuge section for more information or to find manufacturers that sell these products