Background: In clinical practice, GFR assessment by plasma clearance of Tc-99m DTPA is considered standard. The objective was to compare GFR estimation by gamma camera based Gates protocol and S. Creatinine based predicting equations with GFR measured by plasma clearance of Tc-99m DTPA.Materials and Methods: Eighty four patients (50 male and 34 female) underwent Tc-99m DTPA renal scan followed by withdrawal of venous blood samples as per predefined protocol. Gates method GFR (GFRs) was generated. GFR by plasma sampling (GFRp) was calculated by the slope-intercept method with provision for corrections. Cockroft-Gault, 4 variable MDRD and CKD-EPI equations based on serum creatinine were used to generate GFRCG, GFRMDRD, GFRCKD-EPI respectively.Results: GFR estimated by all three estimating equations correlated better than GFRs with GFRp. For estimating GFRp, GFRCKD-EPI had least bias and also was the most precise. GFRs was the least precise method.Conclusion: Three estimating equations based on serum creatinine are superior to Tc-99m DTPA scintigraphy for estimating GFR; CKD-EPI equation being the most accurate and precise.

Introduction: Chronic Kidney Disease (CKD) is becoming a major public health problem worldwide.A remarkable part of health budget is designated annually to control End-Stage Renal Disease (ESRD) in most countries. Managements of ESRD should be provided different renal replacement modalities.Chronic kidney disease increases morbidity and mortality of cardiovascular disease.Methods: This is a descriptive study in rural area around Shahreza, Iran in 2009. A total of 1400 participants over 30 years old selected in a systematic randomized sampling. Glomerular Filtration Rate (GFR) is used as an index of kidney function and albuminuria is used as an index of kidney damage. GFR was estimated using the simplified Modification of Diet in Renal Disease (MDRD) Study equation.and women 6.1%) had GFR less than 60 mL/min/ 1.73 m². The amount of microalbuminuria and macroalbuminuria were 16.2% (women 16.8% and men 15%).12.3% had pyuria (14.6% in women and 7.2% in men) and 12.6% had hematuria (14.6% in women and 8.1% in men). GFR less than 60 ml/ min/1.73 m2 among all age groups and in both sex was significantly different statistically and increased with aging.Conclusions: Considering the prevalence of CKD needs measures to identify the disease sooner. It requires more active national screening program to identify CKD patients in earlier stages and makes sense to integrate such programs in primary health care.

Scintigraphic determination of glomerular filtration rate (GFR) using 99mTc‐DTPA is frequently ordered by urologists. Method by Gates is most commonly used despite that its inaccuracies has been reported in several occasions. In this study we compared Gates method (GFRGates) with a Japanese formula by Inoue et al (GFRInoue) in healthy Pakistani population. In phase‐I of the study GFR values by Gates and Inoue methods in 94 healthy potential kidney donors (25 females and 69 males) were compared with Russell’s two plasma sample clearance method (2‐SC). In phase‐I 616 healthy adults were studied for GFR using Gates and Inoue formulae, 24‐our creatinine clearance (GFRCrCl), and Cockcroft‐ault (GFRCG) methods. In phase‐ Inoue’s method had no statistical significant difference (p value 0.22), good correlation (R=0.69) and least bias (‐.91 ml/min/1.73m2, RMSE=11.85 ml/min/1.73m2) with 2‐SC. Gates method on the other hand tended to underestimate GFR by 20.90% with bias of 25.07 ml/min/1.73m2 and RMSE of 29.97. In phase II GFRInoue had better correlation with GFRGates (r=0.67) compared with GFRCrCl (r=0.13) and GFRCG (r=0.08). GFRCrCl and GFRCG had wider scatters (RMSD=21.27 and 21.59 ml/min/1.73m2 respectively) compared with GFRGates (RMSD=14.53 ml/min/1.73m2). All values of GFR tended to underestimate when compared with Inoue's method. Method by Inoue to measure GFR is more accurate in normal South Asian population.

Using Gates technique for GFR measurement with Gamma camera, the patient is received 5mCi of Tc-99m-DTPA. By this amount of radioactivity, good quality renal scan is not possible. This study tries to optimize Gates technique for GFR measurement during routine renal scan (with 10-15 mCi). Methods and materials: Scanning was performed for 60 seconds from samples of Tc-99m with activities of 3, 9, 12, 15 and 18 mCi in a small syringe, with a 30 cm distance from the detector. Another sample of 12 mCi of Tc-99m was imaged for 5, 10, 15, 20 and 30 seconds. The same sample was again imaged for 10 seconds in different distances (10, 20, 30 and 40 cm) from the detector. Each image was acquired 10 times. Using rectangular region of interest (ROI), total count and maximum count per pixel were recorded for all images.Results: The total count revealed rising in the images form 3 mCi to 15 mCi samples while declining thereafter, suggesting paralysis of the Gamma camera in high activities. Maximum count per pixel was 32767 (2 in 15 power minus one) in all images except for the 3 mCi sample image, suggesting saturation of the pixels in high activities. Also saturation of the pixels was note in images of 12 mCi sample for more than 15 seconds. No saturation of pixels was noticed within 20-40 cm distance from the detector. Conclusion: By optimization of the Gates technique for GFR measurement, GFR can be calculated during routine renal scan. We suggest using 10-15 mCi of Tc-99m-DTPA, with 5-15 seconds preinjected syringe count, 30 cm distant from the detector. Comparison of GFR calculation using suggested technique with GFR estimation by creatinine clearance in 9 patients, resulted in a significant and good correlation coefficient (R=0.883, P=0.005).

Cystatin C is a 13 KD basic protein that is a member of the cystatin super-family of cysteine protease inhibitors. The cystatin C gene seems to be a house keeping gene, which is compatible with a stable production rate of cystatin C by most cells. This protein is freely filtered through the glomerulus and almost completely reabsorbed and catabolized by proximal tubular cells. Because of these characteristics cystatin C is assumed to be a better marker of glomerular filtration rate than other markers. 115 new cases of renal disease aged between 14 and 88 years and 121 healthy subjects, aged between 11 and 78 years were studied. In all of the subjects serum cystatin C and creatinine were determined and creatinine clearance was determined only in patients. Cystatin C was determined by a particle-enhanced turbidimetric assay and creatinine was measured by Jaffe's method. In addition, to assess the diagnostic efficiency of serum cystatin C in comparison to that of serum creatinine and creatinine clearance in predicting changes in GFR, we performed Tc99m - DTPA clearance on 53 subjects including controls and patients. A linear relationship was found between Tc99m - DTPA clearance and 1/ serum cystatin C (r= 0.712, p-value <0.001), 1/serum creatinine (r= 0.709, pvalue < 0.001) and creatinine clearance (r= 0.777, p- value <0.001). Diagnostic accuracy in the identification of reduced GFR measured as area under the receiver-operating characteristic plot was 0.878±0.050 (Mean±SE) for cystatin C, 0.866±0.051 for creatinine and 0.866±0.051 for creatinine clearance. The serum cystatin C reference values (mean±1.96 SD) determined was 0.83 - 0.88 mg/L. A cutoff cystatin C concentration of 0.82 mg/L had 92% sensitivity and 79% specificity for detecting abnormal GFR. There was no significant correlation between cystatin C and age (p- value <0.219) and weight (p- value <0.193). This study demonstrates that serum cystatin C has an increased diagnostic accuracy for reduced GFR when compared with serum creatinine and creatinine clearance. Hence, cystatin C seems to be an alternative for the estimation of GFR.