Microhaematocrit (Mhct) or Packed Cell Volume (PCV) tests require the use of good quality capillary tubes manufactured with good quality glass. Capillary tubes are either plain or pre-coated with heparin, and are commonly used to extract small blood samples directly from the vein by using a lancet.
Our centrifuge consumables range includes both 40mm and 75mm capillary tubes. This type of tube is not only used for Packed Cell Volume tests, but also the extremely useful function of transporting small volumes of sample to other devices, such as microscope slides for making blood smears and Petri dishes for other tests.
Why Is The Quality Of Capillary Tubes So Important?
It is very important that capillary tubes are manufactured correctly using good quality material with a consistent bore diameter. Furthermore, the thickness of the wall must not only be strong enough to withstand centrifugal G-forces of up to 10,000 RMP but also thin enough to allow easy viewing of the reading. Finally, a good quality capillary tube should not break when pushed down into the sealant tray, and neither should the sealant plug become detached from the tube. See our Top Tips below.
Other Centrifuge Consumables
The length of your cristaseal capillary tubes will depend on the make of your centrifuge. We supply a Superior Glass brand of 75mm capillary tubes which fit our VetSpin Duo centrifuge as well as other standard size centrifuges such as Hawksley and Centurion. Our Superior 40mm capillary tubes fit our VetSpin Micro range of benchtop mini centrifuges as well as the StatSpin VT. Our full range of centrifuge consumables and accessories includes quality sealant trays; microcentrifuge tubes, blood collection tubes; readers and our popular Vet-Tube racks (available in a range of bright colours) to hold your samples.
Hawksley Reader – for microhaematocrit measurement
This Hawksley Microhaematocrit Tube Readers are designed to read 75mm capillaries or 40 mm capillaries and to give the client years of service. Choose a Hawksley reader as it is precision printed with an intuitive reader scale which will give fast, easy and accurate haematocrit measurements. No other product in the marketplace will give you this level of solid quality at such a modest cost.
Fast and easy to read
Intuitive reader scale
High quality – made from machined components
Precision printing and assembly
How to use the Reader
Position the tube in the slot within the acrylic slider. The Reader’s baseline must intersect the base of the red cells.
Carefully move the tube holder slide, making sure the top line intersects the top of the plasma.
Adjust the knob on the left-hand side of the reader; this moves the line under the slider. Make sure that the middle line intersects the top of the red cells.
Read the percentage PCV on the scale located on the right of the tube reader.
Top Tips For Sealing Capillary Tubes
Top Tips For Sealing Capillary Tubes
Sometimes, when the end of a capillary tube is withdrawn from the sealant tray, the sealant wax can remain attached to the tray rather than inside the capillary tube.
Carefully push the capillary to the bottom of the tray, and then twist the capillary before it is withdrawn from the sealant vertically. Use a Kimberly-Clark Professional lint-free medical wipe to clean down the end of the tube after sealing.
The sealant plug can also become detached during centrifuging leading to the loss of the sample.
Plugging the capillary tube twice will help to ensure there is no sample loss. It’s also important to remember to ensure that the sealant trays are kept at ambient temperature – if the sealant wax becomes too warm and soft it is likely to fail to seal the capillary during centrifugation.