Since the diagnosis of CV requires the presence of cryoglobulins
in serum, appropriate sample collection and handling is crucial.
may exhibit variable ultrastructural appearances.
There are three types of cryoglobulins
, which differ in their composition.
A few things to consider: RBC results and MCV may be falsely elevated due to the WBCs being counted simultaneously with RBCs and platelets; a spun hematocrit is approximately 2% to 5% higher than a calculated hematocrit; hemoglobin may be falsely elevated due to turbidity; MCH and MCHC values may be inaccurate due to the affected parameters from which they're calculated; and falsely elevated WBC values may be seen in samples with cyofibrinogen, cryoglobulins
, nucleated red blood cells, micromegakaryocytes, or any particle sized in the range that is counting WBCs.
In a large prospective study, Cacoub et al (13) discovered cryoglobulins
in 54% of all patients with HCV, one-third with type II cryoglobulinemia and two-thirds with type III cryoglobulinemia.
40] Other related deposits, such as light chain deposition disease, fibrillary, immunotactoid, and deposits of cryoglobulins
, should be considered in the differential diagnosis.
In their protocol for the investigation of cryoglobulins
, the authors advocate the use of the "cryocrit" as a means of quantifying and typing the cryoglobulin
Tests for autoimmune disorders: Detection of systemic lupus Antinuclear antibody (ANA), erythematosus, vasculitides, anti-neutrophil cytoplasmic systemic sclerosis, Sjogren antibody (ANCA), (b) syndrome, antiglomerular basement anti-glomerular basement membrane antibody disease, membrane antibody, (b) cryoglobulinemia, rheumatoid factor/ hypocomplementemic renal diseases cryoglobulins
, (b) serum C3 (lupus nephritis; and C4 complements membranoproliferative, post-infectious and cryoglobulinemic glomerulonephritis).
When patients present with clinical symptoms of systemic autoimmune diseases during the initial evaluation, other laboratory tests that can be helpful include IFM-ANA, RF, cryoglobulins
, and circulating immune complexes.
sample dilution by intravenous fluids, storage of blood samples at reduced temperature, instrument failure, plugging of sample probes with clots, separator gel or cryoglobulins
, sampling errors from inadequate samples or from bubbles in samples, or interfering substances) (1-3).
Potential etiologies of autoimmune hemolytic anemia were ruled out (tests for HIV, autoimmune hepatitis and cryoglobulins
assay were negative).
Subsequent proficiency tests have included benign and malignant body fluid differentials, hemacytometer cell count calculations on body fluids, manual reticulocyte counts, and blood smear scans for WBC and PLT interferences such as platelet clumping, nucleated red blood cells, and cryoglobulins