Cryoglobulinaemia: clinical and laboratory perspectives.

Cryoglobulins are immunoglobulins that precipitate in the serum upon cooling to below core body temperature and re-dissolve at higher temperatures. Cryoglobulinaemia may be life-threatening. The three types of cryoglobulinaemia are associated with a wide spectrum of haematological, autoimmune, and chronic infectious diseases, especially hepatitis C infection. Our laboratory has received 378 requests for cryoglobulin testing over the past 5 years, with a detection rate of 4.8% in the 271 patients involved. Twelve per cent of the specimens were not processed due to being at an inappropriate temperature on arrival at the laboratory. Clinicians should be aware of temperature requirements when requesting cryoglobulin testing in suspected cases, and for all relevant protein tests in patients with cryoglobulinaemia. Handling specimens at inappropriate temperatures in the pre-analytical and analytical phases of the investigation might lead to cryoprecipitation and therefore false-negative results. The potential pitfalls encountered with specimen handling, analysis, and result interpretation are discussed in detail.