Evaluation Of Serum Cystatin Research Articles

Evaluation of serum cystatin C levels in multiple myeloma: diagnostic significance and clinical implications

Cystatin C (CysC) levels in patients with multiple myeloma (MM) have been linked to tumour load and outcomes’ prediction. This study aimed at assessing the diagnostic utility of CysC in distinguishing MM patients from controls and advanced stages of MM. In total, 98 MM patients and 57 healthy controls participated in this cross-sectional case-control study. Demographic, clinical, and biochemical data were assessed. The study groups exhibited significantly diverse measures of urea, creatinine, CysC, β2-microglobulin, and lactate dehydrogenase activity. β2-Microglobulin was found to be a reliable predictor for both the MM staging and its diagnosis, but CysC was found to only possess a partial capacity of predicting advanced MM stages. Our results highlight the significance of taking into account many biomarkers in the therapy of MM, so as to achieve effective clinical evaluation. More research is required in order to clarify the CysC implication in the prognosis and management of MM.

Evaluation of serum cystatin C as an early marker of renal disease in Chronic Kidney Disease patients in Kano

Chronic Kidney Disease (CKD) is a public health problem with rising incidence worldwide. Nigeria appears to be badly hit by this epidemic; therefore, there is a need to assess a more reliable marker devoid of limitations. This study evaluated serum cystatin C as an early biochemical marker of renal disease in chronic kidney disease patients in the Kano metropolis. A cross-sectional study was conducted at Aminu Kano Teaching Hospital and Muhammad Wase Specialist Hospital (MWSH) in Kano, Nigeria. A total of 150 subjects comprised 100 chronic kidney disease patients, and 50 apparently healthy subjects as controls. The serum creatinine was measured by the Jaffe Method, cystatin C by immunoturbidometric method, and glomerular filtration rates were estimated using CKD-EPI and modified diet in renal disease formulae. One-way Analysis of Variance was used to compare the Estimated Glomerular Filtration Rate (eGFR) of the chronic kidney disease patients with the control groups. In this study, the multiple comparisons of the estimated glomerular filtration rate showed that cystatin C-based glomerular filtration rate gave a direct and accurate measurement of independent of age, and muscle mass with the estimated glomerular filtration rate of ≤60 mL/min/1.73m2 in chronic kidney disease patients substantially lower as compared to the control group and newly diagnosed chronic kidney disease patients. Serum cystatin C-based glomerular filtration rate gave a direct and accurate measurement of independent of age, and muscle mass and thus suggestive of a better marker of early detection of chronic kidney disease. Creatinine-based glomerular filtration rate has been relatively inexpensive and widely used for the diagnosis of renal function. However, to address its limitations caused by the influence of some factors, cystatin C-based glomerular filtration rate gave a direct and accurate measurement independent of age, sex, and muscle mass.

Evaluation of serum cystatin C level as an early biomarker of nephropathy in children with type 1 diabetes mellitus attending Suez Canal University Hospital

Background Diabetic nephropathy is a syndrome characterized by a secondary renal disease in patients with diabetes mellitus (DM). It is a serious complication of DM and is the most common cause of the end-stage renal disease. Aim To evaluate the diagnostic value of serum cystatin C level as an early biomarker of nephropathy in children with type 1 diabetes mellitus (T1DM) attending Suez Canal University Hospital. Patients and methods This was a descriptive cross-sectional study that included 49 children with T1DM attending the pediatric endocrinology outpatient clinic of at Suez Canal University Hospital, Ismailia, Egypt, and 49 matched healthy controls during the period from 1/12/2020 to 1/3/2021. The target population was children with T1DM aged between 6 and 18 years of both sexes who were attending the pediatric endocrinology outpatient clinic of Suez Canal University Hospital, Ismailia, Egypt. All studied patients and healthy controls were subjected to history taking and general and systemic examination. The following investigations were done: fasting blood sugar, serum creatinine, estimated glomerular filtration rate, albumin/creatinine ratio (ACR), urine analysis, hemoglobin A1C, and serum cystatin C level). Results ACR and cystatin C levels were significantly higher in albuminuric than nonalbuminuric diabetic patients. There was a significant positive correlation between serum cystatin C and duration of diabetes, hemoglobin A1C, and ACR. For serum cystatin C, regarding detection of microalbuminuria, the sensitivity was 66.7%, specificity was 75%, the positive predictive value was 49%, and the negative predictive value was 0.52%, with the best cut-off value of 0.98 (mg/l). Conclusion Microalbuminuric diabetic patients showed an increased serum cystatin C levels, whereas their creatinine levels were still within normal. Serum cystatin C levels well reflect the severity of renal damage caused by DM. The serum cystatin C measurement might become a useful, practical, noninvasive, and accurate tool for early detection of microalbuminuria and renal insufficiency in T1DM.

Evaluation of serum Cystatin C as an early diagnostic marker in non-dialysis CKD patients as compared to serum creatinine.

Objective: To test the hypothesis that Serum cystatin C is an early diagnostic marker in non-dialysis CKD patients as compared to serum creatinine. Study Design: Descriptive, Cross Sectional OPD/ Hospital Based study. Setting: Department of Biochemistry and Nephrology, Jinnah Postgraduate Medical Centre, Karachi. Period: January 2018 to December 2018. Material & Methods: Study subjects included the diagnosed cases of Chronic Kidney Disease (CKD) up to 4th stage with exclusion of patients on dialysis. A total 90 subjects of age above 18 years who were presenting to the Nephrology clinic of JPMC for screening and evaluation of chronic kidney disease were recruited after applying inclusion and exclusion criteria. Results: There was significant mean difference in all eGFR across studied groups with p-value lower than 0.05. Cystatin C based calculation of GFR is lower in all three groups (86.33±13.08, 18.73±8.44, 73.30±12.23) as compared to GFR calculated based on serum creatinine (102.33±17.84, 30.00±11.59,. Our study was also suggestive that the sensitivity of serum Cystatin C is higher as compared to creatinine for detection of reduced GFR. Conclusion: Our study shows that cystatin C is a reliable indicator of estimating kidney functions as compared to serum creatinine. A possible advantage of cystatin C is that being a large molecule, its blood levels might rise sooner than that of creatinine.

THE EFFECT OF SUKUN LEAF (ARTOCAPTUS ALTILIS) EXTRACT ON RENAL ISCHEMIA/REPERFUSION INJURY IN WISTAR RATS WITH PARAMETER OF KIDNEY HISTOPATHOLOGICAL FINDINGS SERUM CYSTATIN-C AND SERUM CYSTATIN-C

Objective: To determine the effects breadfruit leaf extract (Artocaptus altilis)in Wistar rats, which had induced renal ischemic-reperfusion injury, with evaluation of serum cystatin C level and kidney histopatologic findings. Material & Methods: A total of 30 Wistar rats, three groups of ten, were included in the study and were performed in Bandung Eijkman Animal Laboratory. In group I (sham group), a right nephrectomy was done. In group II (control), a right nephrectomy was also done and the left renal pedicles were occluded for 60 minutes and reperfused for 60 minutes. In group III (treatment), the treatment was equal with group II, and breadfruit leaf extract (4.75%) was administered intraperitoneally. At the end of the study, a left nephrectomy was performed on all groups. Afterward, serum cystatin C levels and kidney histopathological findings of all rats were examined. Data were analyzed by an unpaired numerically comparative analysis with SPSS 20.0 software. Results: The mean of serum Cystatin C in group I was 3183.2 ± 680.9 pg/dL, group II was 3776.4 ± 326.7pg/dL, and group III was 3492.7 ± 1.326.7pg/dL. The mean of histopathology renal score was also assessed, group I was 4.4 ± 0.52, group II was 8.6 ± 0.84, and group III was6.3 ± 1.70. Comparative test of serum cystatin C level, using ANOVA test and Benferroni post hoc test, in the treatment group has a p-value of > 0.05, it showed that there were no significant differences on the value of cystatin C level on the treatment group. In correlation test of renal histopathology score, suing Kruskal-Wallis test and Mann-Whitney post hoc test has a p-value of < 0.05, therefore there were significant differences on the mean value of renal histopathology score in the treatment group, with Eta correlation coefficient 0.847. Conclusion: The beneficial effects of breadfruit leaf extract can be attributed to its protective effects on renal cells damage. This treatment has an important role in reducing renal injury resulting from renal ischemia-reperfusion. However, breadfruit leaf extract did not significantly improve renal function based on serum cystatin C level. 

Evaluation of Serum Cystatin C Levels And Its Relation with CEA, CA 19-9 in Patients with Gastric and Colorectal Cancer

Amaç: Böbrek fonksiyonun bir belirteci olarak bilinen sistatin C’nin tümör gelişiminde inhibör etki gösterdiği düşünülmektedir. Çalışmada bilinen böbrek hastalığı olmayan mide ve kolorektal kanserli olgularla sağlıklı bireylerin serum sistatin C düzeyleri arasındaki olası farkın, serum karsinoembriyonik antijen (CEA) ve karbohidrat antijen 19-9 (CA19-9) düzeyleri arasındaki ilişkinin incelenmesi amaçlanmıştır.Materyal ve metod: Çalışmaya serum kreatinin konsantrasyonu referans aralığı içerisinde yer alan ve tahmini glomerüler filtrasyon hızı (eGFH) >60 mL/dk olan mide (n=35) ve kolorektal kanserli (n=35) hastalar ile bilinen herhangi bir sistemik hastalığı olmayan sağlıklı bireyler (n=40) dahil edilmiştir. CEA ve CA 19-9 testleri kemilüminesans temelli immün yöntemle (Beckman Coulter UniCel® DxI 800 Immunoassay System) Sistatin C analizi ise partikül yüzeyi genişletilmiş immünotürbidimetrik yöntem (Roche Diagnostics Cobas® Modular P®) kullanılarak yapılmıştır.Bulgular: Mide, KRK (kolorektal kanser) ve kontrol grupları arasında serum kreatinin konsantrasyonu açısından önemli fark izlenmezken (p=0,571) sistatin C düzeyi hasta gruplarında kontrol grubuna göre anlamlı olarak daha yüksek izlenmiştir (p<0,001). Çoklu değişkenli lojistik regresyon analizinde sistatin C düzeyinin yüksek olması üzerinde sırasıyla; kreatinin düzeyi ve kanser hastası olmanın etkili olduğu bulunmuştur. Kreatinindeki her 0,1 mg/dL’lik artış sistatin C düzeyinin yüksek olma ihtimalini 2,531 kat (%95 güven aralığı: 1,562-4,100) arttırmaktadır (p<0,001). Ayrıca kontrol grubuna göre kanserli grupta sistatin C’nin yüksek olma ihtimalinin 20,384 kat (%95 güven aralığı: 2,992-142,196) fazla olduğu bulunmuştur (p=0,002). Hasta grubunda yer almak, yaş, cinsiyet ve kreatinin konsantrasyonu gibi faktörlerin etkileri göz önünde bulundurulduğunda CEA ve CA 19-9 yüksekliği ile serum sistatin C düzeyi arasında anlamlı ilişki izlenmemiştir (p>0,05). Sonuç: Mide veya kolorektal kanserli olgularda serum sistatin C düzeyinin böbrek fonksiyonunun yanısıra kanser varlığından da etkilenebileceği gözlenmiştir.Anahtar Kelimeler: Sistatin C, Katepsin, Mide Kanseri, Kolorektal Kanser

Early Detection of Renal Impairment Among Patients with Type 2 Diabetes Mellitus Through Evaluation of Serum Cystatin C in Comparison with Serum Creatinine Levels: A Cross-Sectional Study.

BackgroundThe proportion of patients with end-stage renal disease caused by diabetes has progressively increased during the last few decades. Serum creatinine level is the most commonly used biochemical parameter to estimate GFR in routine practice. However, 50% of GFR can be lost before significant elevation of serum creatinine. Cystatin C is found to be a new promising marker for early detection of renal diseases.Objective of the StudyThe aim of this study was to determine the value of serum cystatin C and serum creatinine levels for early detection of renal disease in patients with type 2 diabetes mellitus.MethodologyA hospital-based comparative cross-sectional study was conducted with a sample size of 120. For early detection of renal disease in patients with type 2 diabetes mellitus, serum creatinine and cystatin C levels were measured and compared.Result and DiscussionSerum creatinine and cystatin C levels were significantly increased in patients with type 2 diabetes mellitus compared to healthy controls. The mean±SD value of serum creatinine was found to be 0.87±0.44 mg/dL in patients and 0.63±0.27 mg/dL in control. Serum cystatin C level was also found to be significantly (P=0.0001) higher in patients (0.92±0.38 mg/L) compared to controls (0.52±0.20 mg/L). The mean±SD of eGFR in three equations (Creatinine Equation, Cystatin C Equation, and Creatinine–Cystatin C Equation) were 105.7±27.5 mL/min/m2, 90.4±28.2 mL/min/m2, and 100±29.5 mL/min/m2, respectively.ConclusionCystatin C-based GFR estimation equations detect renal impairment in patients with type 2 diabetes mellitus earlier than creatinine-based GFR estimation equations.

Evaluation of Serum Cystatin C as an Early Biomarker of Acute Kidney Injury in Patients with Acute Pancreatitis.

IntroductionAcute pancreatitis (AP) is an inflammatory process of pancreas with varying degree of involvement of regional tissues. The aim of this study was to investigate the potential use of serum cystatin C (Cys-C) for the early and accurate diagnosis of acute kidney injury (AKI) in patients of AP.Materials and methodsThis was a prospective study conducted in 1 year. Total of 215 cases of AP fulfilling the inclusion criteria were enrolled in this study. Patients suffering from chronic pancreatitis, neoplasm, chronic liver disease, and chronic kidney disease were excluded from the study. Diagnosis of AP was based on the Atlanta classification 2012. All patients were classified into a non-AKI group (n = 152) and an AKI group (n = 38) according to the dynamic changes in serum creatinine levels. Serum Cys-C was measured by particle-enhanced immune nephelometric assay.ResultsBy univariate logistic regression analysis, body mass index (BMI) (OR = 1.44, 95% CI: 1.23–1.68; p < 0.001), blood urea (OR = 1.15, 95% CI: 1.06–1.23; p < 0.001), Cys-C (OR = 1.04, 95% CI: 1.01–1.07; p < 0.05), serum calcium (OR = 0.59, 95% CI: 0.41–0.86; p < 0.05), and serum lactate dehydrogenase (LDH) (OR = 1.001, 95% CI: 1.0–1.001; p < 0.05) were the significant indicators for AKI in patients with AP. Using multivariate logistic regression analysis, urinary albumin and Cys-C were independent and significant indicators of AKI in patients with AP (OR = 1.026, 95% CI: 1.01–1.07; p < 0.01). Receiver operating characteristic (ROC) curve of serum Cys-C, for AKI in patient with AP could be identified with a sensitivity of 92.06% at specificity of 96.0% [area under the curve (AUC) = 0.96, 95% CI: 0.92–0.98] by baseline serum Cys-C (cutoff value = >32.32 mg/L).ConclusionIncrease of baseline serum Cys-C was associated with AKI in patients with AP.How to cite this articlePatel ML, Shyam R, Bharti H, Sachan R, Gupta KK, Parihar A. Evaluation of Serum Cystatin C as an Early Biomarker of Acute Kidney Injury in Patients with Acute Pancreatitis. Indian J Crit Care Med 2020;24(9):777–782.

Evaluation of serum cystatin C levels in fibroid patients in Elele

Evaluation of serum cystatin C levels in fibroid patients in Elele

Evaluation of Serum Cystatin C Levels in Fibroid Patients in Elele

This study was aimed at determining the serum levels of Cystatin C in fibroid patients. A total of 140 women were recruited for the study, 70 served as control while 70 were fibroid patients (test). Nephelometric Immunoassay Method in Mispa autoanlyser was used for the assay. The data were analyzed with statistical package for social science (SPSS) version 20. The results showed significant difference (P<0.05) when Cystatin C in fibroid subjects (2.6 ± 1.11 mg/dl) were compared to control (1.0 ± 0.34 mg/dl) and there was significant difference (P<0.05) when Cystatin C levels were compared among the different age groups. It was concluded that Cystatin C was elevated in fibroid women.

Evaluation of Serum Cystatin C compared with Creatinine: A study in patients with Pre-eclampsia

This is cross sectional study aim to evaluate of serum Cystatin C and Creatinine level among pre-clampsia patients. Hundred subjects were evaluate in this study, 50 preclampsia patients as cases and 50 healthy apparently as control groups. Serum Cystatin C and Creatinine were measuring using MISP-i2, Mindray respectively. In assessment of renal function and compare with creatin in women which diagnostic preeclampsia. Result showed there was significant increase in mean concentration of Cystatin C in case versus control groups with P-value 0.000, insignificant different in Creatinine level when compare case group with control group with P-value 0.706. The study conclude that serum Cystatin C is higher in preclampsia patients while Creatinine show insignificant different as serum Cystatin C as marker for glomerular filtration, may be useful as marker for renal disease in preclampsia.

Evaluation of Serum Cystatin C as a Marker of Early Renal Impairment in Patients with Liver Cirrhosis

Background. Serum cystatin C (CysC) was proposed as an effective reflection of the glomerular filtration rate (GFR). However, its role in patients with liver cirrhosis has not been extensively verified especially in the detection of early RI. Patients and Methods. Seventy consecutive potential candidates for living donor liver transplantation with serum creatinine (Cr) <1.5 mg/dL were included. CysC, Cr, and estimated GFR [creatinine clearance (CCr), Cockcroft-Gault formula (C-G), MDRD equations with 4 and 6 variables, CKD-EPI-Cr, CKD-EPI-CysC, and CKD-EPI-Cr-CysC] were all correlated to isotopic GFR. Early RI was defined as GFR of 60–89 mL/min/1.73 m2. Results. Patients were 25.7% and 74.3% Child-Pugh classes B and C, respectively. GFR was ≥90, 60–89, and 30–59 mL/min/1.73 m2 in 31.4%, 64.3%, and 4.3% of the patients, respectively. All markers and equations, except C-G, were significantly correlated to GFR with CKD-EPI-Cr-CysC formula having the highest correlation (r = 0.474) and the largest area under the ROC curve (0.808) for discriminating early RI. At a cutoff value of 1.2 mg/L, CysC was 89.6% sensitive and 63.6% specific in detecting early RI. Conclusion. In patients with liver cirrhosis, CysC and CysC-based equations showed the highest significant correlation to GFR and were measures that best discriminated early RI.

Evaluation of serum cystatin C as an indicator of early renal function decline in type 2 diabetes

ObjectivesThis study was conducted to evaluate the clinical usefulness of cystatin C levels in the serum in predicting renal impairment in patients with type 2 diabetes.BackgroundIn clinical practice, the glomerular filtration rate is often estimated from plasma creatinine levels. Several studies have shown cystatin C to be a better marker for the diagnosis of impaired renal function.Materials and methodsPlasma samples were obtained from 20 healthy individuals and 40 patients with diabetes mellitus type 2 for the determination of the levels of creatinine and cystatin. In addition, we classified all participants according to the urine albumin/creatinine ratio.ResultsPatients were categorized into the following groups depending on their urine albumin/creatinine ratio (mg/g creatinine): macroalbuminuric, microalbuminuric, and normoalbuminuric. There were no significant differences in age and sex between the three groups. However, the estimated glomerular filtration rate was significantly lower in the macroalbuminuric group compared with the microalbuminuric and normoalbuminuric groups, and cystatin C showed a highly significant difference in detecting early decline in diabetic patients.ConclusionFrom this study, we concluded that estimation of the serum cystatin C level is a useful, practical, and noninvasive tool for early detection of renal impairment in the course of diabetes.

Evaluation of serum cystatin C and treating efficacy of enalapril for contrast induced nephropathy after percutaneous coronary intervention

Objective To investigate the evaluation of serum cystatin C and treating efficacy of enalapril for contrast induced nephropathy after percutaneous coronary.intervention.Methods 86 patients who need coronary angiography or coronary stents implantation by skin were divided into observation group(43 cases)and control group(43 cases)randomly.The fasting venous blood was extracted and in which Cys-C and Scr were tested.All the patients were given water therapy,and enalapril was added in observation group.Diversification of concentration of Cys-C and Scr and efficacy of enalapril were recorded.Results There was no difference of Cys-C and Scr in serum and eGFR before and after operation(all P＞0.05),and the concentration of BUN was(3.96±0.89)mmol/L,which was lower after operation(P＜0.05),and the rate of CIN incidence was 2.33 ％(1 case).The concentration of Cys-C in serum was(18.4±0.58)mg/L,which was significantly higher than preoperation(P＜0.05),and there was no significant difference of Scr,eGFR and BUN before and after operation(P＞0.05),and the rate of CIN incidence was 11.63％(5 cases).Conclusion Cys-C was more sensitive in early detection for contrast induced nephropathy and more convenient.The rate of CIN incidence could be decreased by using enalapril. Key words: Cys-C; Contrast,nephropathy; Enalapril; Examine; Efficacy

Evaluation of Serum Cystatin C for Diagnosis of Acute Rejection after Renal Transplantation

ObjectiveTo evaluate the clinical value of serum cystatin C (ScysC) for the diagnosis of an acute rejection episode after renal transplantation. MethodsThe 76 recruited renal transplant patients included 43 without and 33 with an acute rejection episode. We determined the values of serum creatinine (Scr), blood urea nitrogen (BUN), β2 microglobulin (β2-MG), uric acid (UA), and ScysC before surgery and at 1, 3, 5, 7, 14, 30, and 90 days thereafter. The glomerular filteration rate (GFR) was measured by 99mTc-DTPA to evaluate correlations. ResultsNo significant difference was observed between the groups before surgery (P > .05). In the rejection-free group ScysC was decreased by 48.1% at 1/day after surgery which was greater than the other cohorts. In the rejection group at day 3 the ScysC increased which was earlier than others. The highest coefficient correlation was observed between ScysC and GFR. The AUCROC of ScysC was greater than all of the others. ConclusionScysC was a more sensitive marker to detect changes in renal function than Scr, BUN, β2-MG or UA; therefore it can be used to predict an acute rejection episode after transplantation.

Evaluation of serum cystatin C levels and 99mTechnetium‐mercaptoacetyltriglycine‐3 renal scintigraphy for the early detection of cisplatin‐induced renal toxicity in cancer patients

SUMMARY: Cisplatin has a broad‐spectrum antineoplastic activity. Nephrotoxicity is a prominent component of the toxicity profile of cisplatin‐based chemotherapy. In recent years, several reports have confirmed that cystatin C (cys‐C) demonstrates a better correlation with the glomerular filtration rate than with serum creatinine. Scintigraphic techniques are also widely used in evaluating renal function. In the present study, serum cys‐C, serum creatinine concentrations and 99mTechnetium‐mercaptoacetyltriglycine‐3 (99mTc‐MAG‐3) scintigraphy were studied in 22 cisplatin‐naive cancer patients, 3 days before and 24 h after the first cycle of cisplatin‐based chemotherapy. Serum cystatin C and creatinine levels increased in cancer patients after chemotherapy (creatinine: from 68 ± 12 to 72 ± 17 nmol/L; cystatin‐C: from 0.064 ± 0.025 to 0.072 ± 0.033 jimol/L), but these differences were not statistically significant (P&gt;0.05). Semiquantitative variables of 99mTc‐MAG‐S scintigraphy significantly elevated after chemotherapy (T½*: from 10.27 ± 5.00to 16.17 ± 9.40 min, R20/max*: from 0.40 ± 0.12 to 0.67+0.45, Tmax**: from 5.40 ± 4.01 to 7.59 ± 5.30 min; *P&lt;0.001, **P&lt;0.01, respectively). These results suggest that MAG‐3 scintigraphy is a highly sensitive method in the early detection of cisplatin‐induced nephrotoxicity. Serum cystatin C doesn't seem to play a role in the early detection of cisplatin‐induced nephrotoxicity. As a result, MAG‐3 scintigraphy may be used in selected patients who have a predisposition for renal toxicity.

Evaluation of serum cystatin C and chromogranin A as markers of nephropathy in patients with Type 2 diabetes mellitus

Nephropathy is a significant cause of morbidity and mortality in patients with diabetes mellitus (DM). The condition is characterized by persistent albuminuria and years of progressive renal structural changes associated with decline in the glomerular filtration rate (GFR). This study evaluates whether serum concentrations of the endogenous markers of GFR, cystatin C and chromogranin A could be used as indicators of nephropathy in 77 patients with Type 2 DM. On the basis of early morning urine microalbumin:creatinine ratio, patients were divided into patients without diabetic nephropathy (DN) who were normoalbuminuric (n = 27) and patients with DN who were microalbuminuric (n = 8) or macroalbuminuric (n = 42). Patients with reduced GFR or elevated serum cystatin C did not show the expected increase in serum chromogranin A. Twenty-six percent of the patients with normoalbuminuria and 6% of those with DN had serum chromogranin A below the detection limit of the assay (< 2 U/L). In patients with DN, serum chromogranin A showed significant correlation with serum cystatin C, but not with serum creatinine and creatinine clearance. Serum cystatin C and creatinine showed poor correlation with duration of DM and HbA1c. Serum cystatin C and creatinine were significantly higher in patients with DN than in normoalbuminuric patients. Serum cystatin C showed significant correlation with serum creatinine (rs = 0.45, p = 0.002), but not with creatinine clearance (rs = 0.23, p = 0.17) in patients with DN. Four of nine patients with creatinine clearance between 50 and 80 mL/min had increased (> or = 1.4 mg/L) serum cystatin C compared with only two patients with increased serum creatinine concentration. Twenty of 50 (40%) patients with DN had elevated serum cystatin C compared with 6 of 50 (12%) with elevated serum creatinine. If microalbuminuria is regarded as the "gold-standard" test, serum cystatin C has a sensitivity of 40% and specificity of 100% for the detection of DN. However, further studies are required to confirm the usefulness of serum cystatin C estimation as a screening test and as an early indicator and predictor of the development of DN.