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 in question.
From a theoretical standpoint, the use of the cryocrit is rather dubious because it assumes that different cryoproteins pack and sediment with equal volumes.
Other investigators have reported an apparent inverse relationship between the cryocrit and vasculitis (2).
In the setting of a chronic, untreated HCV infection and evidence of nephrotic syndrome, a cryocrit was requested to investigate the possibility of membranoproliferative glomerulonephritis secondary to cryoglobulinemia.
A cryocrit of 5% was reported for 2 blood samples drawn on different days after storage of serum at 4[degrees]C for 10 days.
Consequently, the patient began a combination therapy of pegylated interferon a and ribavirin and demonstrated some improvement in his proteinuria, plasma viral load, and cryocrit. He has an ongoing requirement for large doses of diuretic therapy to control his peripheral edema; he was not deemed suitable for kidney and/or liver transplantation.
Some laboratories determine cryocrit, and others quantify total protein content.
Of the 127 laboratories included for the postidentification phase, 50 (39%) reported the cryocrit, the total protein content, and/or the immunoglobulin concentration in the cryoprecipitate (quantitative); 48 (38%) answered negative/ positive only; and 29 (23%) provided additional information without reporting the cryoglobulin concentration in the cryoprecipitate (nonquantitative).
Total protein content and cryocrit are only indirect measures of the cryoglobulin concentration because they also detect the presence of other proteins such as albumin and fibrinogen.
(a) Patient Cryoglobulin Cryocrit
, Peak at Peak at no.
Patient Disease Cryocrit
, % 1 Lymphoplasmacytoid immunocytoma 7 2 Waldenstr6m macroglobulinemia 15 (immunocytoma) 3 Centroblastic lymphoma 4 4 Waldenstrom macroglobulinemia 40 (immunocytoma) (Gelatinous appearance) CD4000 CD4000 optical impedance Patient count count 1 355 356 2 619 578 3 94 66 4 476 572 CD4000 Technicon H*3 immunoplatelet platelet Patient (CD61) count count 1 42 445 2 226 819 3 21 23 4 329 422 Hemacytometer (chamber) Patient count 1 38 2 289 3 22 4 318
After blood is collected at 37[degrees]C and serum separated, 5 mL of the serum is allowed to stand in a cryocrit
tube at 4[degrees]C for 2-7 days, and formation of the precipitate is confirmed visually.