Sample Type
Bloods
Associated Problems
Solution
Insufficient
We would always recommend taking much more sample than is
needed. This is handy because we store the serum/plasma for up to a
month after the request date and it makes it much easier to do
further work ups if more tests are required.
So how many bottles? Only ever fill up 1 EDTA (unless of course you
are requesting an anaemia investigation, then you should really send
2 or 3 especially if you are looking for a coombs test). The rest of the
blood should be used to fill either heparin or serum bottles. There is
little value in sending both. A few tests specifically require serum.
You can refer to our QUICKGUIDE or the reverse of the pricelist for
this information but as a general rule, EDTA is only usable for
haematology and DNA – we can’t do any other tests on it. Serum
tends to be better than heparin for most things.
Aged samples will haemolyse, so if you have left your sample
overnight or over a weekend you can be almost guaranteed that it
will haemolyse. The only way to avoid this is to spin and separate.
Only spin serum/heparin samples, never spin EDTA, and remove the
clear layer on the top and place it in a clean sterile LABELLED tube.
Sometimes haemolysis occurs whilst the sample is being taken and
this is usually a result of the shearing forces exuded through a finer
gauge needle. 21g is the recommended size but the bigger the needle
the less chance there is of haemolysis.
Is the serum/plasma milky looking? This is fat or lipid and usually
occurs after feeding. Fasted samples can limit the amount of lipaemia
that occurs. Lipaemia is sometimes clinically significant.
Icterus is normally clinically significant and cannot be avoided.
Clotted EDTA samples are useless. Clots occur if the sample is left in
the syringe for too long or once placed in the EDTA tube, not mixed
sufficiently. Always check the expiry date of the EDTA tube as
sometimes this can affect the anticoagulant effects. Check before you
post it as this will eliminate any delays in processing.
Sometimes clots can occur in serum, avoid this by allowing half an
hour after the blood has been taken before spinning/separating.
Try and use the small plastic microtubes as these are more robust in
transit. Ensure that the lid is fitted correctly to prevent leakage.
We’re always trying to reuse packaging so if you are in need, then
give us a call and we’ll send some down to you.
Is the animal on antibiotics? Sometimes the antibiotic may not kill
the causative agent but will prevent its proliferation. The bug will
therefore remain and continue to cause disease. Take the animal off
therapy for 1 week if possible and resample if you are sure that the
cause is microbiological.
Did you get a good sample? Was there material on the swab when
you removed it?
Also, washes and joint fluids very rarely return growth.
Faecal contamination is the most common form of contamination.
This means that there is a heavy mixed growth of E. Coli,
Staphylococci and faecal Streptococci. These bacteria on their own
can be significant, depending on the sample site. We always place
more importance on pure growths of bacteria although faecal
contamination is very common and in some cases unavoidable.
Wrong sample type
Haemolysed
Lipaemic
Icteric
Clotted
Broken in transit
Cultures
No growth
Contaminated
Wrong sample type
High resistance to
antibiotics
Cytology
No cells harvested
Incorrect sample type
Poor quality sample
Culture not possible
Histopathology
Non-diagnostic
Sample leakage
Filling out
Submission Forms
Missing information
NEVER send anything in for culture in EDTA or formalin. Both of these
agents will kill the bacteria. Using transport swabs with included
media (amies) is by far the best. If you need to keep the sample
overnight, DO refridgerate it to prevent overgrowing, it will still be
viable. Urine should be sent in clean sterile universal containers and
refridgerated overnight. Boric acid containers are useful if you
suspect a UTI as the boric acid prevents bacterial proliferation if it
does get contaminated. Faecal samples are best sent in the
appropriate containers that seal sufficiently. NEVER send faeces or
urine in glass containers, and always double check the seal before
sending and package with absorbent material just in case. Please
don’t send faeces in bags or gloves.
Often animals with chronic infections will yield a highly resistant
bacterial strain, normally a result of overuse of inappropriate
antibiotics over a long period of time. The best way to avoid this is to
regularly carry out microbiological testing on suspected bacterial
infections so that the appropriate targeted therapy can be
administered from the outset.
This may be due to a technique issue. FNAs are the best way of
harvesting cells and often a good FNA can remove the necessity to
biopsy a lump. If you would like some tips on taking good cytology
samples, you can contact us here at the lab.
Fluids and washes should be submitted in EDTA as this additive
preserves the cells beautifully.
Again, this might be down to technique. Having too much blood in
the aspirate may obscure the white cell picture. Also, providing slides
is great but the cells must be spread in a monolayer across the slide.
If the cell layer is too thick, it will not be possible to give a full and
accurate description of the cells types present.
If you want a culture on the same case, you MUST supply some fluid
in a plain tube with no additives.
The sample received has not given us much information. A resection
will probably be worthwhile.
Formalin is a hazardous substance and extreme caution must be
exercised when using it. It is very important that the correct sample
pots are used with the formalin (plastic pots that seal securely)and
try and choose a pot that is closest in size to the sample size and
ensure that the formalin covers the entire biopsy. Don’t be tempted
to top it up with H2O if you feel you are a bit short, this will cause
undesirable precipitates which will affect the quality of the sample.
Always package formalin with absorbent material in case of leakages.
It is important that you use the correct submission form for your
samples. We ask you to provide animal details and histories so that
we can give you the best service and interpretation possible. Leaving
out crucial information may lead to delays so PLEASE always fill out
the sub form completely. They are available to download from the
website and we can also post you some if necessary. You can
photocopy blank forms for re-use! We have different forms for
Rabies and Equine submissions.