Laboratory work-up showed a normal complete blood count, a negative antinuclear antibodies (ANA) titer, a negative double-stranded DNA, normal levels of inflammatory markers, and negative cryoglobulins and cold agglutinins
. The patient was diagnosed with pernio.
 If cold agglutinins
were suspected, the sample was collected and immediately incubated at 37[degrees]C and at room temperature for 30 mins.
Then there are those tests that actually benefit from a clotting time spent in an incubator, such as cold agglutinins
, and, in fact, some patient tubes for hematology performing CBCs must be warmed before testing, again, due to cold agglutinins
Finally, although it is possible that monoclonal IgM was undetectable in the serum due to the presence of cold agglutinins
or cryoglobulins, however hemolytic anemia was absent and cold agglutinins
react with human red cells but they differ in the strength of the reaction with different cells.
Erroneous red blood cell parameters due to cold agglutinins
were evident as increases in the MCH in 3 cases in which the operator deviated from protocol, and improper mixing of tubes run in manual mode was the likely explanation for 2 errors.
His tests including full blood count, thyroid function tests, antinuclear antibody, cryoglobulin, cryofibrinogen, cold agglutinins
, antiphospholipid antibodies and serum protein electrophoresis, which were performed to determine the etiology, were within normal ranges.
Mycoplasma pneumonia antibodies and cold agglutinins
were found to be negative.
This should be contrasted with cold agglutinins
which cause agglutination of RBCs.
Formation of cold agglutinins
is frequently observed during Mycoplasma pneumoniae infections.