Evaluation of Early Screening Method Using Turbidity Measurement for Detection of Cryoglobulin

Kim, Jong Woo; Jearn, La He; Kim, Think You

Abstract

OBJECTIVE: Cryoglobulins are immunoglobulins that tend to form reversible precipitations below 37degrees C, well known to be associated with various diseases such as autoimmune diseases, hematologic malignancies, chronic infections and renal diseases. In many cases, low amounts of cryoglobulins take a few days to be precipitated. In this study, we compared cryoglobulin early screening test with conventional method to evaluate its clinical efficacy. MEHTODS: 28 patients who showed cryoglobulinemia were selected and the time it took for visibly detecting the existence of cryoglobulin were recorded. Sera of cryoglobulinemiemic patients (n=19) and of control group (n=14) kept in two conditions of 37 degrees C and 4 degrees C for 1 hour and were then measured for delta optical density (DOD).
RESULTS
In the cryoglobulin early screening test using the test tube, the median and range of the DOD for cryoglobulinemic patient group was 0.50 (0.17~0.99) while it was 0.18 (0.02~0.50) for the control group. The results showed statistically significant difference (p=0.001). In another method of using the microplate, there was no statistical significance between disease and control group. The area under the curve for test tube method was 0.857. The sensitivity and specificity were 89.5% and 71.4% respectively (cut-off value=0.23).
CONCLUSION
Cryoglobulin early screening test provides the results within 2 hours and we thought this feature could give clinicians some helpful informations. More studies are needed in the future for increasing the sensitivity and specificity of this test.