All that's required for a hematocrit is a drop of blood drawn into a capillary tube and spun in a special high-speed centrifuge, then the red portion is measured against a scale as a percentage of the total sample. The drop of blood is easily taken in the same way that owners of diabetic cats do for blood glucose testing, from an ear-prick. The main obstacle to doing this at home is that the centrifuges cost hundreds of dollars.
I've found what appears to be the perfect solution on EBay and it's new equipment assembled by a private party and sold for a reasonable price with a guarantee!
This particular unit has a very attractive feature: normally the open end of a hematocrit capillary must be sealed with clay before centrifuging and the clay is sold in laboratory kits for hundreds of tests, precisely measured with guide holes, etc. These kits are intended for high-production labs and are ridiculously expensive if you just test every couple of weeks or so. The centrifuges described below are assembled from parts originally manufactured for Bayer (sold under the Ames brandname) which don't require the use of clay, as described below.
As it
happens I've got two of the Ames units that I picked up from
military surplus so I can attest to their ease of use. I suspect that
the reason they were discontinued is that they were being
sold for use on the battleground and the plastic cases simply weren't
up to
the rough treatment they were subjected to in the field by relatively
untrained med techs under stress... one of the two I have had minor
plastic damage (hinge on lid, for example) which was fixable... the
mechanism still works fine.
I've
exchanged a number of emails with Ed Brown (the maker) over the
past few days and he sounds very interested in supplying the needs of
folks wanting to take care of their kitties. So much so, in fact, that
he sent me an evaluation unit which I received today, including a
design improvement he wanted my opinion on. I've looked it over
thoroughly and can attest to the quality of workmanship. It's well put
together and with proper handling should give good service.
His
price listed on EBay
is only $136 including shipping, but he told me that part of that
expense is Ebay and PayPal commissions and that he could discount the
price a bit to those ordering directly and paying by check or certified
funds. We've also been discussing other ways to lower the cost such as
reducing the number of included capillary tubes from 500 to 100 and
possibly omitting the battery pack or making it optional. He also has
lancets that he could supply if they're suitable for our
purpose (I'm not sure what kind he has, haven't seen them)..
I figure most people pay between $15 and $50 for each test depending on whether an office visit or drawing fee is charged, so owning one of these would pay for itself with only a few tests. Illustrated instructions for the ear-prick are found on many websites for diabetic cats.
To be honest, I can only think of three things these units might lack when compared with the ones sold for hundreds of dollars more to clinics:
First, they don't have an interlock to prevent operation with the cover open. This shouldn't be a biggie;
Second,
no automatic timer... not all centrifuges have them anyway, and
with hematocrits it's not critical as long as it's run long enough to
pack the cells fully. It only takes a couple of minutes;
Third,
due to the shorter capillary used (32mm instead of 70mm) the PCV is
only readable to about 2% so subtle changes won't be evident.
I think this is a reasonable tradeoff considering the alternative,
dragging our kitties to the vet just for 1% more precision!
I
should probably mention that I'm not involved in either the manufacture
or marketing of this centrifuge and have no connection with Ed Brown
aside from the emails we've exchanged since last week. I just think
it's the greatest opportunity to reduce vet visits since home BP
testing, and a whole lot easier, cheaper and more reliable!
The following is a more detailed description excerpted from Ed's EBay listing (in the configuration currently being supplied):
[The following description by Ed Brown] [Go to comments by Jim Hayes]
This centrifuge will operate on its built-in battery pack containing 4 AA rechargeable batteries, or on any external 6-volt DC source, including that from the supplied AC/DC adaptor which can be used on 110 or 220 volt current.
The unique rotor, designed and originally manufactured by Bayer for its Compur M1100 microhematocrit centrifuge (later the AMES MICROSPIN), uses tiny neoprene seals around the inner edge to seal the tubes, so that the usual clay sealant is not required. The tube is thus completely filled, and may therefore be read by the percentage scale alongside, without being removed from the rotor. Moreover, the tiny 32mm tubes fill instantly from just one large drop of blood.
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As may be seen in the photographs, the rotor clips to the shaft of the motor and is easily removed for disposal of the filled tubes and for cleaning. It is not necessary to balance the rotor if only one, three, or five tubes are being used. When all tubes are in place, press down firmly on the hub to lock the rotor in place, pressing the distal ends of the tubes so tightly against the neoprene seals that they do not leak. After spinning for 2-3 minutes, the level of packed red cells is instantly read from the percentage scale alongside.
When Bayer discontinued the manufacture of the $900 Ames Microspin, I received their permission to obtain the rotor components from their suppliers, and have since assembled the rotors and the complete unit, which has been field-tested by many mission hospitals and clinics throughout the world with overwhelming acclaim. It has also been tested with great success by zoologist researchers in the field, and by veterinarians for checking the blood of farm animals -- and by a pediatrician friend in Georgia who has used one in his office. I am therefore now pleased to offer the unit to others.
The unit is supplied with a supply of capillary tubes and an AC/DC adaptor for use with 110 or 220 AC current.
The unit is fully guaranteed.If you have any questions about this item, please contact me at ewbindy@aol.com
Ebay item # 320035762748 (as of 17 Nov 2006)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320035762748