Clinical application of combination test of serum cystatin C and β2-microglobulin levels in blood and urine samples in hypertension diagnosis

Objective To explore the significance of serum cystatin C (Cys C)and β2-microglobulin (β2-MG) levels in blood and urine samples in hypertension grading and risk stratifying. Methods One hundred and thirty six cases with primary hypertension were enrolled into the study and classified into three grades and four risk stratifications. The serum Cys C levels were determined by ELISA assay. The blood and urine β2-MG were measured by radioimmunoassay. The serum BUN, Cr concentration were measured by the automatic biochemical analyzer. Results The positive rates of urine β2-MG were the highest index in patients with grade 1 (32%) and low risk hypertension( 8% ) ,followed by serum Cys C levels( grade 1 hypertension 24% ) ,compared with other indices( Ps ＜ 0. 05 ). With the blood pressure elevating, as well as the risk stratification increasing,serum Cys C level and the blood, urine β2-MG levels increased gradually by grading and stratifications (Ps ＜0. 05 or Ps ＜0. 01 ). We also found linear regression relationship between serum Cys C ,urine β2-MG levels and the risk stratifications of hypertension( r =0. 851 and r =0. 469 respectively,Ps ＜0. 01 ). The significant changes of serum BUN,Cr were only found in patients with grade 3 or very high-risk hypertension. Conclusion Joint detection of serum Cys C and urine β2-MG may help to detect early glomerular and tubular dysfunction in primary hypertension patients. Serum Cys C and blood, urine β2-MG levels are also related with the occurrence and development of hypertension,which show clinical significance in hypertension prognosis. Key words: Cystatin C;  β2-microglobulin;  Primary Hypertension;  Renal dysfunction