The influence of CTLA-4 single nucleotide polymorphisms on acute kidney allograft rejection in Turkish patients.

Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is a cell surface protein, which down-regulates the immune response at CTLA-4/CD28/B7 pathway. We aimed to investigate the influence of the -318 C/T, +49 A/G, -1661 A/G and CT60A/G, and CTLA-4 gene polymorphisms on acute rejection of kidney allograft in Turkish patients. The study design was a case-control study that consists of three groups: Group 1 (n = 34) represented the kidney transplant (Ktx) recipients who experienced acute rejection, Group 2 (n = 47) was randomly assigned Ktx recipients without acute rejection, and Group 3 (n = 50) consisting of healthy volunteers to evaluate the normal genomic distribution. The polymerase chain reaction-restriction fragment length polymorphism technique was used to determine the polymorphisms. Genotype and allele frequencies among three groups denoted similar distributions for +49 A/G, -1661 A/G, and CT60A/G. Conversely, -318 C/T genotype was three times more frequent in the acute rejection group than in the non-rejection group (OR = 3.45; 95%CI = 1.18-10.1, p = 0.015) and two times more frequent than the healthy control group (OR = 2.45; 95% CI = 0.98 - 6.11, p = 0.047). Additionally, having a T allele at -318 position was significantly associated with acute rejection (0.147 vs. 0.043, OR = 3.45; 95% CI = 1.13-10.56, p = 0.02). 318C/T gene polymorphism and T allelic variant were found to be associated with increased acute rejection risk in Turkish kidney allograft recipients.

Is Klotho F352V Polymorphism the Missing Piece of the Bone Loss Puzzle in Renal Transplant Recipients?

BACKGROUND: Bone disorders are next to cardiovascular problems in frequency in renal transplant (RT) recipients. Reduction in 1,25-dihydroxycholecalciferol (1,25D) levels is among the reasons causing bone loss in these patients. Klotho (KL) serves as a co-receptor for fibroblast growth factor 23 (FGF23), and functions in vitamin D metabolism. KL polymorphisms have been identified in several studies, and phenylalanine to valine substitution at amino acid position 352 seemed to be important to KL function. We investigated KL F352V polymorphism and its relation with 1,25D levels in RT recipients. METHODS: The study included 25 RT recipients (8 female, 17 male) and 26 (14 female, 12 male) healthy control subjects who were wild (FF) phenotypes in terms of KL F352V polymorphism. RT recipients with (FV, n = 11) and without (FF, n = 14) a heterozygote polymorphism were determined with high resolution DNA melting analysis of KL F352V polymorphism. Serum 1,25D levels were measured using the RIA method. RESULTS: RT recipients with FV phenotype had significantly lower 1,25D levels (17.58 ± 18.38 pg/ml) compared to recipients with FF phenotype (44.91 ± 24.68 pg/ml) and control subjects (28.24 ± 12.13 pg/ml). 1,25D levels in RT recipients with FF phenotype were significantly higher than control subjects. CONCLUSIONS: KL F352V polymorphism may increase the expression of FGF23 co-receptor, KL protein and thus may decrease renal expression of 1α-hydroxylase, and/or stimulate 24-hydroxylase in RT recipients. The resultant decrease 1,25D levels may participate in bone loss in these patients.

Lymphocyte and monocyte vitamin D receptor expression during paricalcitol or calcitriol treatments in patients with stage 5 chronic kidney disease.

PURPOSE: In this study, we aimed to investigate the effect of paricalcitol and calcitriol usage on vitamin D receptor (VDR) contents of CD8+ , CD4+ lymphocytes and monocytes in stage 5d chronic kidney disease (CKD) patients. METHODS: Thirty-six hemodialysis patients older than 18 years of age and 19 healthy controls (group HC) without any known acute or chronic diseases were included in the study. The group of patients undergoing scheduled hemodialysis comprised three subgroups: group CL: patients on calcitriol (n: 10), group PC: patients on paricalcitol (n: 13), and group NT: patients not taking any vitamin D or VDR activating medications (n: 13). CD8+/VDR, CD4+/VDR and MONO/VDR values were representing the ratio of VDR representing cells among related cell group. On the other hand, values of CD8+/MFI, CD4+/MFI and MONO/MFI have shown the total amount of cellular VDR content per cell which has been given as of mean fluorescence intensity in the flow cytometric process. Main CKD mineral bone disorder parameters such as a hemogram, serum BUN, creatinine, albumin, Ca, iP, iPTH, 25(OH)D3 levels were also measured. RESULTS: Average VDR contents in CD8+, CD4+ and monocytes were not different among three patient groups on hemodialysis. But in all hemodialysis subgroups, CD8+/VDR, CD4+/VDR, MONO/VDR, CD8+/MFI, CD4+/MFI and MONO/MFI levels were found to be higher compared with the healthy control subjects (p < 0.001). Among hemodialysis groups, no significant CD8+/VDR, CD4+/VDR, and MONO/VDR content differences were found with regard to the type of VDR activator agent used. There was no difference in serum levels of 25(OH)D3 and CRP among groups participating in the study. CONCLUSION: There was no difference between CD8+/VDR, CD4+/VDR, and MONO/VDR levels in hemodialysis patients using calcitriol or paricalcitol, suggesting that both treatment agents may have a similar effect on VDR contents in lymphocytes and monocytes in that patient population. But in all hemodialysis subgroups, CD8+/VDR, CD4+/VDR, and MONO/VDR levels were found to be higher compared with the healthy control subjects, suggesting an overexpression of VDR through a non CRP and/or 25(OH)D3 dependent mechanism.

Advanced oxidative protein products are independently associated with endothelial function in peritoneal dialysis patients.

AIM: Oxidative stress (OS) and asymmetric dimethylarginine (ADMA) are accepted as non-classical cardiovascular risk factors in end-stage renal disease patients. To clarify the role of these factors in the atherosclerotic process, we investigated if OS and ADMA are associated with endothelial function (EF) in peritoneal dialysis (PD) patients. METHODS: Fifty-two non-diabetic PD patients without known atherosclerotic disease as well as 30 age- and sex-matched healthy individuals were included. We measured serum thiobarbituric acid-reactive substances (TBARS), malondialdehyde (MDA), advanced glycation end-product (AGE), pentosidine, advanced oxidation protein products (AOPP), ADMA and EF as described by Celermejer et al. in all subjects. RESULTS: TBARS, MDA, AOPP, AGE, pentosidine and ADMA levels were significantly higher in PD patients than in controls (P < 0.001). Flow-mediated dilatation (FMD)% and nitrate mediated dilatation (NMD)% in PD patients were lower than in the control group (7.7 +/- 4.0% vs 11.70 +/- 5.50%, P < 0.01 and 17.6 +/- 8.3% vs 26.4 +/- 4.6%, P < 0.01). Additionally, it was found that AOPP are independently correlated with FMD% and NMD% in PD patients (beta = -463, P < 0.01 and beta = -420, P < 0.05). CONCLUSION: This study shows that PD patients without known atherosclerotic disease can also be characterized by endothelial dysfunction and AOPP levels independently predict endothelial function level in PD patients.

Improving technique survival in peritoneal dialysis: what is modifiable?

The continuous quality improvement approach in peritoneal dialysis practice necessitates definition of the factors and the procedures that may possibly be contributing to the final success of peritoneal dialysis. The philosophy of continuous quality improvement uses the Plan, Do, Check, Act (PDCA) cycle. To improve the procedures used during peritoneal dialysis, the first step is to create a plan, then to carry out the plan, to check it, and after the collection of satisfactory information, to execute the chosen improvement action. Several studies have identified the most frequent causes of transfer from PD to HD as infection, catheter problems, inadequate dialysis, and psychosocial factors, among others. According to training guidelines from the International Society for Peritoneal Dialysis, seven points are of major importance to decrease infection risks: exit-site care, catheter placement, antibiotic prophylaxis for procedures, prevention of bowel-source peritonitis, prevention of fungal peritonitis, and connection methods. On the other hand, other factors such as hypoalbuminemia, depression, and obesity should also be taken into consideration for better technique survival in peritoneal dialysis patients.

Treatment of secondary hyperparathyroidism with paricalcitol in patients with end-stage renal disease undergoing hemodialysis in Turkey: an observational study.

OBJECTIVE: To evaluate monthly percentage changes of intact parathyroid hormone (iPTH) and other major bone marker levels in patients with secondary hyperparathyroidism (SHPT) undergoing hemodialysis (HD) and receiving paricalcitol. METHODS: A total of 493 (F/M 244/249) adult patients with SHPT who were undergoing HD in 22 HD units and receiving paricalcitol treatment, with iPTH > 300 mg/mL, adjusted serum levels of calcium (Ca) < 10.2 mg/dL, and serum levels of inorganic phosphorus (iP) < 6 mg/dL were included in this multi-center, national, prospective, observational study. Data regarding efficacy, safety, and adverse events of paricalcitol treatment were collected during a 12-month follow-up period through monthly visits along with serum iPTH, Ca, iP, alkaline phosphatase (ALP) and other required biochemistry tests as necessary. Mortality data until 6 months after the end of the study were also investigated. RESULTS: The mean age was 58.3 ± 15.8 years and the mean duration of HD was 6.2 ± 5.5 years, respectively. As of 12th month, mean iPTH values decreased from 646 ± 424 pg/mL to 473 ± 387 pg/mL (p < 0.001); no statistically significant changes were observed in Ca levels (p > 0.05). Serum ALP levels also significantly decreased (p = 0.001) and serum phosphorus levels significantly increased (p < 0.001) during the study observation period. Reasons for early terminations were being lost to follow-up (n = 119, 24.1%), hyperphosphatemia (iP > 6 mg/dL, n = 108, 21.9%), low iPTH levels (iPTH < 150 mg/dL, n = 97, 19.7%), and withdrawal of consent (n = 41, 8.3%). In total 32 patients (6.5%) were prematurely terminated the study with hypercalcemia (Ca > 10.2 mg/dL). 46.9% of those hypercalcemic patients had other anomalies with iP and iPTH levels along with hypercalcemia. CONCLUSION: Paricalcitol treatment, resulted in successful iPTH control. In approximately 6.5% of the patients paricalcitol treatment was discontinued since Ca levels reached > 10.2 mg/dL in those patients. No unfavorable effects on serum phosphorus and Ca-phosphorus (Ca × P) product were observed.

Osteoporosis in the elderly with chronic kidney disease.

Considering the aging dialysis population of today, increasing our knowledge about the nature, diagnosis and the treatment of bone mineral density (BMD) problems in end-stage renal disease (ESRD) patients deserves more attention. Osteoporosis is basicly defined as a decrease in bone mass. Large epidemiological studies in general population have identified several risk factors for osteoporosis including advancing age, female gender, white race, decreased calcium intake, gastric acid suppression therapy, sedentary lifestyle, premature loss of gonadal function, decreased estrogen secretion, thin body habitus, decreased physical activity, cigarette smoking, alcohol abuse, excess glucocorticoid exposure, and possibly some genetic factors. Osteoporosis in ESRD patients is only a part of a wider spectrum of metabolic bone problems, namely uremic osteodystrophy. Therefore, its diagnosis, management and follow-up may differ from the general population and an individualization of diagnosis and definition for dialysis population may be necessary. However, standard diagnostic tools such as dual energy X-ray absorptiometry (DEXA) have been widely used for the assessment of bone mineral deficiency status in ESRD patients. Regardless of the methods, most of the studies are in concordance with a reduced BMD in HD and PD patients. Dialysis patients are known to be at increased risk for low-trauma fractures. Thinning of cortical bone, which is responsible for the largest contribution toward reduced bone mineral content in chronic renal failure results in increased fracture risk. In either normal population and dialysis patients, fracture risk is increased with age. But in dialysis patients, besides age, several other factors may also affect the degree of bone mineral deficiency, and age-BMD relationship may be blunted. Female sex, in hemodialysis patients is negatively associated with total hip BMD. While several studies have been unable to demonstrate any association between BMD and PTH levels, larger body size has been shown to have a significant positive effect on BMD in both hemodialysis and peritoneal dialysis patients. Although they have been used in small groups of chronic kidney disease (CKD) and ESRD patients, because of their potential nephrotoxicity and hypocalcemic effects, use of biphosphonates in renal patients is questionable. Currently, bone biopsy, in order to exclude adynamic bone disease is recommended before beginning treatment with bisphosphonates in chronic kidney disease and dialysis patients.

Effects of some hematological parameters on whole blood tacrolimus concentration measured by two immunoassay-based analytical methods.

OBJECTIVES: Tacrolimus (FK506) is a potent immunosuppressive drug used for prevention of rejection following transplantation. Several methods including immunoassays have been used for monitoring tacrolimus levels. The purpose of the present study was to compare the effects of various hematological parameters on whole blood tacrolimus concentrations which were measured with two different analytical methods, namely the microparticle enzyme immunoassay (MEIA II) and enzyme multiplied immunoassay technique (EMIT). DESIGN AND METHODS: The effects of hematological variables, namely hematocrit (Htc), hemoglobin (Hb), red blood cell (RBC), mean cell volume (MCV), mean cell hemoglobin (MCH), mean cell hemoglobin concentration (MCHC), red cell distribution width (RDW) and platelet (PLT) counts on tacrolimus concentrations (n = 2430 measurements) measured with EMIT (n = 1171) and MEIA II (n = 1259) methods in whole blood samples from kidney or liver or combined kidney-pancreas transplant patients (n = 162) during a 2-year post-transplantation period were compared. RESULTS: The whole blood tacrolimus concentrations measured with MEIA II method were affected much more significantly by hematological parameters than those measured with EMIT method. In MEIA II method, RDW (r = 0.479, P < 0.01) showed a stronger correlation with tacrolimus concentration than Htc (r = -0.239, P < 0.01) in all patients. A negative significant correlation (r = -0.468, P < 0.01) was also observed between the Htc and tacrolimus concentration in patients with Htc values < or =25% in MEIA II method. CONCLUSIONS: The results of the present study suggest that EMIT method might be preferred to MEIA II in determination of whole blood tacrolimus concentrations in anemic transplant patients. For better therapeutic drug monitoring, physicians should be aware of these assay differences. Evaluation of hematologic factors that affect the whole blood concentrations of tacrolimus may be helpful in deciding the dosage of this drug.

Benefits of low dose immunoglobulin in the treatment of refractory CAPD peritonitis and longevity of technical survival on CAPD.

In this study we investigated the long term results of intraperitoneal immunoglobulin (Ig) treatment in continuous ambulatory peritoneal dialyses (CAPD) patients with refractory or relapsing peritonitis. Sixteen CAPD patients (4 female, 12 male) with a mean age of 53 +/- 11 years (40-80), with a mean CAPD duration of 46.2 +/- 4.8 months (17-75) were included in the study. The patients included had a diagnosis of either refractory or relapsing peritonitis unresponsive to appropriate antibiotic therapy. 0.5 g of Ig was added to every exchange bag qid as an adjunctive therapy to the culture based antibiotherapy for 7 days. Intraperitoneal Ig treatment was found to be successful in treating peritonitis in all but one patient. Interestingly, following Ig treatment, long term peritonitis rate decreased significantly compared to the period before treatment (before: 2.2 +/- 0.6 episodes/patient/year vs. after: 0.6 +/- 0.17 episodes/patient/year; P = 0.019). The mean CAPD duration after Ig treatment was 30.5 +/- 5.4 (4-64) months. Out of 16 patients, one patient who was unresponsive, had his catheter removed and was switched to hemodialysis, and four patients with preexisting ultrafiltration failure or inadequate dialysis problems were transferred to hemodialysis after successful treatment of their peritonitis, one patient was transplanted and 10 patients continued on CAPD. We conclude that low dose Ig treatment may be beneficial in the treatment of refractory or relapsing CAPD peritonitis possibly through restoring impaired host defense within peritoneal cavity. This therapy, by preventing further peritonitis attacks, may prolong survival on CAPD.

FGF-23, α-Klotho Gene Polymorphism and Their Relationship with the Markers of Bone Metabolism in Chronic Peritoneal Dialysis Patients.

OBJECTIVE: The aim of the present study was to evaluate the variations of some major bone metabolism markers with reference to klotho gene polymorphism (KGP) and bone mineral density (BMD) values in patients on chronic peritoneal dialysis (CPD). MATERIALS AND METHODS: In 51 CPD patients and 40 healthy persons, assays for intact parathormone (iPTH), fibroblast growth factor 23 (FGF-23), osteoprotegerin (OPG), osteocalcin (OC), procollagen type-1 N terminal propeptide (PINP), beta- crosslaps (beta CTx), tartrate resistant acid phosphatase (TRAP5b), bone alkaline phosphatase (BAP), 1,25(OH)D3, and 25(OH)D3 and α-klotho gene mutations were performed. RESULTS: In CPD patients, 1,25(OH)D3 and 25(OH)D3 deficiency rates were 96% and 94% respectively. iPTH (249 pg/mL vs 39 pg/mL) and FGF-23 (1089 RU/mL vs 153 RU/mL), OPG, OC, PINP, beta CTx, TRAP5b levels were significantly higher in patients. iPTH levels and whole-body BMD values were negatively correlated in patients. The rate of KGP was similar in all groups. CONCLUSION: In CPD patients, besides vitamin D deficiency, high levels of OPG, OC, PINP, beta CTx, TRAP5b were evident. Positive correlation between iPTH levels and BAP and PINP levels suggested a diagnostic value for those markers during the management of CKD MBD. On the other hand, high serum TRAP5b concentrations did not seem to be affected by neither calcitriol treatment nor the severity of hyperparathyroidism. iPTH and FGF-23 levels and whole-body BMD values showed a significant negative correlation. We were unable to show any correlation between KGP and any of the CKD-MBD parameters measured in this study.

Low calcium dialysate increases cardiac relaxation in CAPD patients.

OBJECTIVE: To establish whether changes in serum calcium affect left ventricular (LV) function in continuous ambulatory peritoneal dialysis (CAPD) patients. METHODS: This study was conducted on 28 clinically stable CAPD patients (11 females, 17 males). Left ventricular relaxation and systolic function were echocardiographically examined in all patients during standard dialysate (containing 1.75 mmol/L calcium) treatment. All patients were then changed to low calcium dialysate (1.25 mmol/L calcium) for 1 month and all patients were re-examined echocardiographically. Decrement in isovolumic relaxation time (IVRT) and deceleration time (DT), and increment in the ratio of peak early to peak late diastolic velocities (E/Amax) were admitted as indexes showing improvement in LV relaxation. 17 age- and sex-matched controls were also echocardiographically examined. RESULTS: Deceleration time, interventricular septal thickness at systole (IVSTS) and diastole (IVSTD), and posterior wall thickness at systole (PWS) and diastole (PWD) were higher in CAPD patients using standard dialysate than in normal controls. With the use of low calcium dialysate, DTs were similar but IVSTS, IVSTD, PWS, and PWD values remained higher. In normal controls, E/Amax values were higher than those in CAPD patients using standard dialysate (p < 0.001) and low calcium dialysate (p = 0.009). Serum intact parathyroid hormone level, weight, clinical volume status, and blood pressure were similar throughout the study period. Serum ionized calcium levels were decreased significantly during low calcium dialysate treatment. The changes in IVRT, DT, and E/Amax suggest improvement in LV relaxation during low calcium dialysate treatment. CONCLUSION: Left ventricular relaxation is increased with the use of low calcium dialysate compared with standard dialysate treatment. The idea of possible beneficial effects of increment in LV relaxation on cardiovascular morbidity and mortality deserves further studies.

A short story of Klotho and FGF23: a deuce of dark side or the savior?

Fibroblast growth factor 23 (FGF23) is an osteocyte and osteoblast derived peptide hormone, which requires Klotho as a cofactor for its biologic actions. FGF23 acts as a phosphaturic agent and it is capable of reducing serum inorganic phosphate (Pi) via direct inhibition of renal NaPi-2a transporter in the proximal tubuli, as well as indirectly, via the suppression of calcitriol synthesis. In patients with chronic kidney disease (CKD), circulating FGF23 levels are markedly elevated, while Klotho production is decreased. Experimental observations indicating that lack of activities of both Klotho and FGF23 may cause decreased life span, premature aging and accelerated atherosclerosis and generalized vascular calcifications have raised the question whether FGF23 could be a new risk factor and predictor of cardiovascular (CV) disease in both renal and non-renal patient groups. Clinical studies, however, have yielded conflicting results. Some of these studies have found that serum FGF23 is independently associated with mortality and CV events in CKD patients, while others have failed to show any relationship. Furthermore, some studies have even suggested that FGF23 may have a protective role against vascular calcifications and CV disease. Thus, there is clearly a need for further research in this area, and special interest should be paid to the physiologic consequences of high FGF23/low Klotho state, which is typical for patients with CKD.

Use of peritoneal ultrafiltration in the elderly refractory congestive heart failure patients.

BACKGROUND: Refractory congestive heart failure (RCHF), due to its high mortality and hospitalization rates, is a growing health problem. In this study, as an alternative and/or supportive treatment to conventional medical therapies, we have evaluated the clinical value of peritoneal ultrafiltration, performed as a single daily exchange with icodextrin or conventional dextrose-based peritoneal dialysis solutions, in elderly patients with RCHF. METHODS: This was an observational study of 6 elderly patients with RCHF and non-terminal chronic kidney disease (CKD). Their mean age was 72.8 ± 4.9 years. Four of the six patients had NYHA class 4 and two had NYHA class 3 RCHF and a medical history of 18.6 ± 14.9 days/year hospitalization on average, due to decompensated congestive heart failure (CHF). Their baseline glomerular filtration rate, as calculated by the MDRD formula was 49.4 ± 14.6 mL/min/1.73 m(2). During hospitalization, patients were initially treated with several sessions of continuous veno-venous hemofiltration and, following the achievement of hemodynamic stabilization, peritoneal ultrafiltration was initiated as the maintenance ultrafiltration modality. Patients were followed up monthly in terms of their clinical status, hospitalization rates, weight changes, serum sodium levels, and renal function. Echocardiographic changes were also evaluated every 3 months. RESULTS: All patients tolerated peritoneal ultrafiltration well, their functional status improved by 1 or 2 NYHA classes to reach a mean of NYHA class 2 CHF status. During the follow-up period, with a mean daily ultrafiltration rate of 850 ± 176 mL, no hospitalization for decompensated CHF or acute renal failure was required. The patients' renal function was well preserved, with a mean GFR of 49 ± 14.6 mL/min/1.73 m(2) at baseline and 51.6 ± 22.9 mL/min/1.73 m(2) at the 6th month of the study. Additionally, their mean serum sodium levels increased from 128 ± 5.7 mEq/L to 138 ± 5 mEq/L. Echocardiographic evaluation did not show any significant changes during the observation period. No peritonitis or other non-infectious complication of chronic peritoneal dialysis was seen in any of the patients. CONCLUSIONS: Peritoneal ultrafiltration seems to be an efficient and safe procedure and a treatment of choice in elderly patients with RCHF without non-terminal CKD. Peritoneal ultrafiltration improves the quality of life and the effort capacity, and reduces hospitalization rates due to decompensated heart failure and acute renal failure.

Uremic toxins: a new focus on an old subject.

The uremic syndrome is characterized by an accumulation of uremic toxins due to inadequate kidney function. The European Uremic Toxin (EUTox) Work Group has listed 90 compounds considered to be uremic toxins. Sixty-eight have a molecular weight less than 500 Da, 12 exceed 12,000 Da, and 10 have a molecular weight between 500 and 12,000 Da. Twenty-five solutes (28%) are protein bound. The kinetics of urea removal is not representative of other molecules such as protein-bound solutes or the middle molecules, making Kt/V misleading. Clearances of urea, even in well-dialyzed patients, amount to only one-sixth of physiological clearance. In contrast to native kidney function, the removal of uremic toxins in dialysis is achieved by a one-step membrane-based process and is intermittent. The resulting sawtooth plasma concentrations of uremic toxins contrast with the continuous function of native kidneys, which provides constant solute clearances and mass removal rates. Our increasing knowledge of uremic toxins will help guide future treatment strategies to remove them.

The efficacy of urinalysis, plain films, and spiral CT in ED patients with suspected renal colic.

We determined the diagnostic value of urinalysis and plain films in patients with suspected renal colic presenting to an emergency department (ED). Over a 1-year period, 138 patients presented to the ED during the daytime with suspected renal colic, but for technical reasons the diagnostic modalities used in the study could be completed for only 99 patients, and 34 patients were lost to follow-up. A urinalysis; kidney, ureter, and bladder film; and spiral computed tomography (CT) were performed on each patient. The presence of urinary tract stones was determined by their definite presence on helical CT and/or passage of a stone on clinical follow-up (average follow-up = 3 months). A urinary stone was visualized on spiral CT or passed in the urine in 54 of the patients. Using helical CT findings or passage of a stone as the gold standard, plain radiography had a sensitivity of 69% and specificity of 82%. Urinalysis had a sensitivity of 69% and specificity of 27%. The sensitivity increased to 89% if either test was positive, but the specificity remained low at 27%. The sensitivity and specificity of CT in the diagnosis of urinary stones was 91%. Urinalysis and plain films are much less accurate than helical CT for confirming the diagnosis of acute urolithiasis. Further evaluation of the clinical and cost-effectiveness of helical CT should be done to determine its role in the work-up of these patients.