Diagnostic Value Of Serum Cystatin C,Serum RBP And Urinary RBP In Detecting Subclinical Hepatorenal Syndrome In Patients With Liver Cirrhosis

【Objective】 To set up new quantitative determination methods of assaying serum cystatin C(Cys C), serum retinol binding protein (RBP) and urinary RBP concentration by means of Enzyme-linked immunosorbent assay (ELISA), and to investigate the diagnostic values of serum Cys C, serum RBP and urinary RBP as markers of detecting subclinical hepatorenal syndrome (HRS) in patients with liver cirrhosis. 【Methods】 Ninety patients with liver cirrhosis were investigated and divided into Group 1-simple liver cirrhosis group(creatitnine clearance (Ccr)≥80 ml?min-1?1.73 m -2, n=43), Group 2-subclinical HRS group (40≤Ccr＜80ml?min-1?1.73 m -2,n=28) and Group 3-HRS group (Ccr＜40ml?min-1?1.73 m -2,n=19). Serum Cys C, Serum creatinine (Scr) and blood urea nitrogen (BUN) were assayed and compared with those of 26 healthy persons as control group. According to Child-pugh classification,26 ,40 and 24 patients were in Group A,B and C respectively. Serum Cys C, serum RBP and urinary RBP were measured by ELISA. Scr, Ucr and BUN were detected on the automated clinical biochemistry system (HITACHI 7600-010) with Jaffe method and UV-GLDH method, respectively. Diagnostic tests were taken for serum Cys C and serum RBP.【Results】 1. In patients with liver cirrhosis, the serum concentration of Cys C was significantly higher, but the serum and urinary RBP levels were significantly lower, than that in the healthy controls. 2. As the Ccr decreased, the serum Cys C levels increased gradually from group 1, through group 2, to group 3, all the difference being statistically significant(P＜0.01), while there were not marked difference in Scr and BUN between group 1 and 2. The serum and urinary RBP levels in group 2 were significantly lower than those in group 1,but higher than those in group 3. However, only the Scr and BUN levels in group 3 were significantly higher than those in other groups.3.The serum Cys C levels increased gradually from Child-pugh A, through Child-pugh B, to Child-pugh C, all the difference being statistically significant (P＜0.01). The serum RBP and urinary RBP levels decreased gradually from Child-pugh A, through B, to C group. The difference of urinary RBP level between Child-pugh B,C and Child-pugh A, control group being statistically significant (P＜0.01). However, only the Scr and BUN levels in Child-pugh C group were significantly higher than those in other groups.4. Serum Cys C and Scr were negatively correlated to Ccr(r=－0.91 and r=－0.72,P＜0.01),while serum RBP and urinary RBP were positively correlated to Ccr(r=0.80 and r=0.74,P＜0.01). 5.Dignositic tests: (1)Receiver-operating characteristics (ROC) analysis showed that the areas under the curves(AUC) of serum Cys C was 0.819,and the AUC of serum RBP was 0.711.(2)The sensitivity (Se),specificity(Sp) and agreement rate of serum Cys C were 80.2% ,85.62% and 93.2%, and those of serum RBP were 77.32%, 72.47% and 91.72%(P＜0.05); The Se, Sp and agreement rate of Scr were 43.18%,62.49% and 54.16%. (3)The positive predictive value(＋PV) and negative predictive value(－PV) of serum Cys C were 88.23% and 92.59%, and those of serum RBP were 86.66% and 87.50%.(4)The observing concordance of serum Cys C was 96.54%, and it of serum RBP was 89.32%.The Kappa value of serum Cys C was 0.7769, and it of serum RBP was 0.7510. (5)The Se, Sp,＋PV and －PV of parallel test were 93.33％, 86.66％, 77.77％ and 96.30％,and those of serial test were 70％, 96.66％, 91.3％ and 86.57％,respectively.【Conclusions】 1.Serum Cys C and serum RBP detecting could demonstrate the slight renal dysfunction in cirrhotic patients, and may be more sensitive than Scr and BUN; 2.Serum Cys C and serum RBP may be useful makers in detecting subclinical HRS in patients with liver cirrhosis; 3. The combination of low serum and low urine RBP may be more helpful in the early recognition of HRS; 4.The new quantitative determinations of assaying Serum Cys C, serum RBP and urinary RBP are simple, accurate and practical, thus merit further clinical use.