Abstract: PO2258
Asymptomatic Spurious Hyperuricemia Related to Waldenstrom Macroglobulinemia
Session Information
- Pathology and Lab Medicine: Clinical
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Report
- 1602 Pathology and Lab Medicine: Clinical
Authors
- Goyal, Pankaj, Universisty of Cincinnati Academic Health Center, Cincinnati, Ohio, United States
- Gudsoorkar, Prakash Shashikant, Universisty of Cincinnati Academic Health Center, Cincinnati, Ohio, United States
- Thakar, Charuhas V., Universisty of Cincinnati Academic Health Center, Cincinnati, Ohio, United States
Introduction
Increased IgM has been shown to result in underestimation of uric acid levels and pseudo-hypouricemia; however, there are no reported cases of hyperuricemia in the setting of paraproteinemia. We present a case of Waldenstrom’s Macroglobulinemia (WM) resulting in marked elevation of uric acid level in the absence of tumor lysis syndrome (TLS).
Case Description
A 73-year-old man with history of WM was incidentally noticed to have very high uric acid level of 37.2 mg/dl. He had no history of crystal arthropathy or chronic kidney disease. He was started on Acalabrutinib because of high serum viscosity and elevated IgM level. After 30 days of treatment, his serum viscosity and uric acid levels improved significantly, however the treatment had to be discontinued due to development of potential drug related adverse events. After discontinuation of Acalabrutinib, his serum viscosity and uric acid level gradually increased back to the previous level. Laboratory parameters were not suggestive of TLS and potassium, calcium and phosphorus were all normal. 24-hour uric acid excretion was noticed to be low normal (341 mg/24 hours). He was treated with allopurinol and monitored in clinic with serial uric acid checks. He continued to remain asymptomatic despite of having a uric acid level consistently above 35 mg/dl. He was not treated with Rasburicase due to lack of symptoms and potential false elevation of uric acid in the setting of paraproteinemia.
Discussion
Paraproteins often cause factitious biochemical measurements by forming opaque precipitates with the test reagents and interfering with various automated assays. These interferences may be difficult to anticipate as they are intermittent and patient specific. Ultrafiltration of paraproteins, dilution or deproteinization of the samples can sometimes help correct these measuring errors.
WM and other paraproteinemia may cause true hyperuricemia in the setting of TLS. However, the absence of other concomitant laboratory abnormalities should raise a suspicion of factitious results. An observant clinician should be aware of these findings in order to avoid unwarranted testing and treatment. Also, a very high level of uric acid in the absence of symptoms may point towards a possibility of undiagnosed paraproteinemia.