Frequently Asked Questions
What
anticoagulants are suitable for the collection of whole blood or
plasma samples?
Suitable anti-coagulants are
EDTA, citrate and heparin.
Can cloudy
serum or plasma samples be used with the Clearview IM
test?
No. Sample cloudiness
is usually a result of sample contamination. Plasma or serum
samples should be clear and particulate free.
Can haemolysed whole
blood samples be used with the Clearview IM test?
Haemolysed blood samples are
usually indicative of a poor sample quality or old sample.
Whilst not affecting the results, a haemolysed blood sample may
cause staining to the test window making result interpretation more
difficult.
What
are the storage conditions for serum and plasma
samples?
If the serum or plasma
samples are not to be tested immediately they may be stored at
2-8oC for up to 3 days or frozen at -20oC for
up to 1 month.
What
are the storage conditions for whole blood samples?
Whole blood must be tested
the same day. It is not possible to store whole blood
samples.
How should the
Clearview IM test be stored?
Clearview
IM should be stored between 2°C and 30°C. If the tests are
stored in the refrigerator, they must be allowed to reach room
temperature before use.
How
critical is the timing and are the results stable?
With Clearview
IM timing is critical, the test should be read at 5
minutes with serum or plasma samples and 15 minutes with whole
blood samples. It is not possible to read the results after
these read times.
Would a negative result conclude
that a patient does not have Infectious mononucleosis?
Not necessarily. It has been
reported that 10-20% of infected adults and 50% of children under 4
years of age may fail to produce any IM heterophile at all.
Also if a sample (adult) is taken too soon the IM heterophile
antibodies may not have had time to develop.
How soon after the
onset of symptoms should a Clearview IM test be carried
out?
It has been reported that IM
heterophile antibodies are usually demonstrable one week after the
onset of the illness (60-70% of adult patients), peaking at 3-4
weeks (80-90% of adults). Therefore if testing is carried out
too soon then false negative results will occur which is the case
for all IM heterophile antibody tests.
Does a
Clearview IM test result always indicate an acute Infectious
mononucleosis infection?
No. In some cases the IM heterophile antibodies may
persist for several months. Therefore a positive result
should not be regarded as indicative of acute Infectious
mononucleosis in isolation from the clinical and haematological
information.