No Relationship between Serum and Salivary β2- Microglobulin Levels in A Sample of Adult Diabetic Men with Chronic Kidney Disease without Renal Replacement Therapy

OBJECTIVE Β2-microglobulin (β2M) associated amyloidosis is an inevitable complication of chronic kidney disease (CKD). Testing β2M in the blood is invasive and expensive. On the other hand, oral fluid is a perfect medium to be explored for public health and disease surveillance. However, it has never been studied if salivary concentration of β2M reflects its concentration in the serum. The current study; therefore, aimed to examine the relationship between salivary and serum β2M in a sample of adult diabetic men with CKD. MATERIALS AND METHODS Among diabetic patients referred to the Nephrology Department of The Golestan Hospital of Ahvaz due to CKD, 40 men not requiring renal replacement therapy were consecutively recruited for this cross-sectional study. Patients were excluded if they had any disease or were using any drugs that might affect the oral mucosa or saliva. The concentration of β2M was measured in both serum and saliva. The correlation between serum and salivary β2M was measured by calculating spearman's ρ. RESULTS The Spearman's ρ for correlation between serum and salivary β2M was -0.017 (p=0.917), indicating lack of correlation. Serum and salivary creatinine (Spearman's ρ=0.54; p value<0.001) as well as serum and salivary urea nitrogen levels (Spearman's ρ=0.39; p value=0.014) were correlated. CONCLUSION Salivary β2M levels poorly agreed with serum β2M levels, and thus may not be used as a surrogate for serum β2M in CKD patients who did not require replacement therapy.