Centrifuge

Laboratory Equipments

---

Microscope | Centrifuge | Refractometer | Chemistry Analyzers | Hematology Analyzers | Coagulation Analyzers | Quality control of all laboratory equipments


CENTRIFUGE

Another key component of the clinical laboratory is the centri-fuge. Numerous centrifuge types exist for different purposes, such as those for microhematocrit, fecal, urine, and blood samples. It is not uncommon to use a multiuse centrifuge that can be set to spin at a speed appropriate for the biological sample, with specialized holding devices for each type of sample. The manufacturer’s guide should be used for operation, maintenance, and cleaning instruc-tions.

Microhematocrit Centrifuge

This centrifuge is used exclusively for spinning down microhematocrit tubes. Devices intended to determine the blood’s hematocrit—the ratio of red-cell volume to whole blood volume, expressed as a decimal, a fraction, or a percentage. Microhematocrit centrifuges may be used to help diagnose blood loss, polycythemia (an elevation of the erythrocyte count to above-normal levels), anemia, bone marrow failure, leukemia, and multiple myeloma. High hematocrit levels indicate dehydration and erythrocytosis

Basic microhematocrit centrifuge components include a motor that supplies power to the shaft and rotor, centrifuge heads (carriers) that spin on the rotor, and a lid latch and/or lid. The centrifuge head contains the cups or shields that cover the rotor and turns on a spindle. A safety shield in the chamber surrounds the rotor. These centrifuges may or may not use brushes to conduct electricity. Some microhematocrit centrifuges have a reading scale, capillary tube reader, a timer, a braking system, tachometer, and a potentiometer. Some models are equipped with an LCD (liquid crystal display) or LED (light-emitting diode) display and a keyboard, enabling the user to program a specific speed or view device status.

Centrifuges apply centrifugal force to separate suspended particles from a liquid or to separate liquids of different densities. These liquids can include body fluids (e.g., blood, serum, urine), commercial reagents, or combinations of the two with other additives. By creating forces many times greater than gravity, centrifuges can greatly accelerate separations that occur naturally as a result of density differences. The microhematocrit
centrifuge, a special-purpose version of a fixed-head unit, quickly attains speeds of 11,000 rpm and RCFs (relative centrifugal forces) of up to 15,000 g to spin microcapillary tube samples. These tubes require only small blood samples taken from a puncture site or from an anticoagulated venous blood specimen. This centrifuge is used for spinning microhematocrit tubes only. It is preset to 10,000 rpm.

Clinical Centrifuge

Clinical centrifuges are available in two main types: a variable angle centrifuge or a fixed angle centri-fuge. The variable angle centrifuge (also called a horizontal centri-fuge) has swinging buckets that hold the specimen tubes. As the centrifugation begins, these buckets swing out horizontally, and the particles within the specimen are pushed to the base of the tube to form the sediment. Once the rotation stops, the buckets return to their upright position. This change of position from horizontal to vertical can result in a slight remixing of the sample. This effect should be taken into consideration when preparing a sample.

The fixed angle centrifuge has buckets that are in a fixed position, typically about 50° The specimen tubes are held in this position for the entire centrifugation process.



StatSpin

Another option is the StatSpin. This centrifuge is a fixed angle centrifuge designed for small samples. It has a faster spinning speed, and as a result, a shorter processing time.