Utility of fractional excretion of urea in acute kidney injury with comparison to fractional excretion of sodium: A systematic review and meta-analysis.

BACKGROUND: Differentiating between intrinsic and prerenal acute kidney injury (AKI) presents a challenge. Here, we assessed the performance of the fractional excretion of urea (FEUrea) and compared it to the fractional excretion of sodium (FENa) in distinguishing intrinsic from prerenal AKI. METHODS: A thorough search was conducted in several databases until January 16, 2024. We included studies evaluating FEUrea, with or without FENa, for differentiating AKI etiologies in adults. We assessed the methodological quality using the QUADAS-2 and QUADAS-C tools. We performed a meta-analysis using the bivariate random effects model, with subgroup analyses to explore the impact of diuretic therapy on FEUrea, and direct statistical comparisons between FEUrea and FENa involving the subgroups with and without diuretics. RESULTS: We included 11 studies with 1108 hospitalized patients. Among eight studies (915 patients) evaluating FEUrea >35% for distinguishing intrinsic from prerenal AKI, the pooled sensitivity and specificity were 66% (95% CI, 49%-79%) and 75% (95% CI, 60%-85%), respectively. In a subset of six studies (302 patients) comparing FEUrea at 35% to FENa at 1% in patients not receiving diuretics, there were no significant differences in sensitivity (77% versus 89%, P = 0.410) or specificity (80% versus 79%, P = 0.956). In four studies, 244 patients on diuretics, FEUrea demonstrated lower sensitivity (52% versus 92%, P < 0.001) but higher specificity (82% versus 44%, P < 0.001) compared to FENa for the diagnosis of intrinsic AKI. CONCLUSIONS: FEUrea has limited utility in differentiating intrinsic from prerenal AKI. FEUrea does not provide a superior alternative to FENa, even in patients receiving diuretics.

Spray Cryotherapy for Benign Large Airway Stenosis: A Multicenter Retrospective Cohort Study of Safety and Practice Patterns.

BACKGROUND: Benign airway stenosis (BAS) represents a significant burden on patients, providers, and healthcare systems. Spray cryotherapy (SCT) has been proposed as an adjunctive treatment to reduce BAS recurrence. We sought to examine safety and practice variations of the latest SCT system when used for BAS. METHODS: We conducted a retrospective multicenter cohort study in seven academic institutions within the Interventional Pulmonary Outcomes Group. All patients who underwent at least one SCT session with a diagnosis of BAS at the time of procedure at these institutions were included. Demographics, procedure characteristics, and adverse events were captured through each center's procedural database and electronic health record. RESULTS: A total of 102 patients underwent 165 procedures involving SCT from 2013 to 2022. The most frequent etiology of BAS was iatrogenic (n = 36, 35%). In most cases, SCT was used prior to other standard BAS interventions (n = 125; 75%). The most frequent SCT actuation time per cycle was five seconds. Pneumothorax complicated four procedures, requiring tube thoracostomy in two. Significant post-SCT hypoxemia was noted in one case, with recovery by case conclusion and no long-term effects. There were no instances of air embolism, hemodynamic compromise, or procedural or in-hospital mortality. CONCLUSION: SCT as an adjunctive treatment for BAS was associated with a low rate of complications in this retrospective multicenter cohort study. SCT-related procedural aspects varied widely in examined cases, including actuation duration, number of actuations, and timing of actuations relative to other interventions.

Tumor Genesis Syndrome Presenting as Severe Hypophosphatemia in a Patient With T-Cell Acute Lymphoblastic Leukemia.

Tumor lysis syndrome (TLS) is a medical emergency that can develop in leukemias and lymphomas as a first presentation or after the initiation of anti-neoplastic regimens. On the other hand, tumor genesis syndrome (TGS) is a rare condition associated with certain malignancies, especially those with a high neoplastic burden characterized by rapid proliferation, leading to avid uptake of phosphorus from the serum and culminating in hypophosphatemia. Interestingly, a combination of TLS and TGS can occur simultaneously in a subset of patients. This leads to the development of hypophosphatemia instead of the hyperphosphatemia commonly associated with TLS. We herein present a case of severe asymptomatic hypophosphatemia in a patient with an incidental finding of T-cell acute lymphoblastic leukemia. The patient was initially diagnosed with TLS with hypophosphatemia, but further investigation revealed that the patient had isolated TGS.

The safety of intravenous peripheral administration of 3% hypertonic saline: A systematic review and meta-analysis.

BACKGROUND: Three percent hypertonic saline (3% HTS) is used to treat several critical conditions such as severe and symptomatic hyponatremia and increased intracranial pressure. It has been traditionally administered through a central venous catheter (CVC). The avoidance of peripheral intravenous infusion of 3% HTS stems theoretically from the concern about the ability of the peripheral veins to tolerate hyperosmolar infusions. The aim of this systematic review and meta-analysis is to assess the rate of complications associated with the infusion of 3% HTS using peripheral intravenous access. METHODS: We conducted a systematic review and meta-analysis to assess the rate of complications related to the peripheral infusion of 3% HTS. We searched several databases for available studies that met the criteria until February 24th, 2022. We included ten studies conducted across three countries examining the incidence of infiltration, phlebitis, venous thrombosis, erythema, and edema. The overall event rate was calculated and transformed using the Freeman-Tukey arcsine method and pooled using the DerSimonian and Laird random-effects model. I2 was used to evaluate heterogeneity. Selected items from Newcastle-Ottawa Scale2 were used to assess the risk of bias in each included study. RESULTS: A total of 1200 patients were reported to have received peripheral infusion of 3% HTS. The analysis showed that peripherally administered 3% HTS has a low rate of complications. The overall incidence of each of the complications was as follows: infiltration 3.3%, (95% C.I. = 1.8-5.1%), phlebitis 6.2% (95% C.I. = 1.1-14.3%), erythema 2.3% (95% C.I. = 0.3-5.4%), edema 1.8% (95% C.I. = 0.0-6.2%), and venous thrombosis 1% (95% C.I. = 0.0-4.8%). There was one incident of venous thrombosis preceded by infiltration resulting from peripheral infusion of 3% HTS. CONCLUSIONS: Peripheral administration of 3% HTS is considered a safe and possibly preferred option as it carries a low risk of complications and is a less invasive procedure compared to CVC.

Diagnostic Performance of Fractional Excretion of Sodium for the Differential Diagnosis of Acute Kidney Injury: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVES: AKI is classified as prerenal, intrinsic, and postrenal. Prerenal AKI and intrinsic AKI represent the most common causes for AKI in hospitalized patients. This study aimed to examine the accuracy of the fractional excretion of sodium for distinguishing intrinsic from prerenal AKI. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, the Cochrane Library, and Scopus for all available studies that met the criteria until December 31, 2021. We included studies that evaluated fractional excretion of sodium in differentiating AKI etiologies in adults, whereas studies that did not have sufficient data to extract a 2×2 table were excluded. We assessed the methodologic quality using the Quality Assessment of Diagnostic Accuracy Studies-2 tool and extracted the diagnostic accuracy data for all included studies. We conducted a meta-analysis using the bivariate random effects model. We performed subgroup analysis to investigate sources of heterogeneity and the effect of the relevant confounders on fractional excretion of sodium accuracy. RESULTS: We included 19 studies with 1287 patients. In a subset of 15 studies (872 patients) that used a threshold of 1%, the pooled sensitivity and specificity for differentiating intrinsic from prerenal AKI were 90% (95% confidence interval, 81% to 95%) and 82% (95% confidence interval, 70% to 90%), respectively. In a subgroup of six studies (511 patients) that included CKD or patients on diuretics, the pooled sensitivity and specificity were 83% (95% confidence interval, 64% to 93%) and 66% (95% confidence interval, 51% to 78%), respectively. In five studies with 238 patients on diuretics, the pooled sensitivity and specificity were 80% (95% confidence interval, 69% to 87%) and 54% (95% confidence interval, 31% to 75%), respectively. In eight studies with 264 oliguric patients with no history of CKD or diuretic therapy, the pooled sensitivity and specificity were 95% (95% confidence interval, 82% to 99%) and 91% (95% confidence interval, 83% to 95%), respectively. CONCLUSIONS: Fractional excretion of sodium has a limited role for AKI differentiation in patients with a history of CKD or those on diuretic therapy. It is most valuable when oliguria is present.

Acute Hemorrhagic Leukoencephalitis - A Rare but Fatal Form of Acute Disseminated Encephalomyelitis - Complicated by Brain Herniation: A Case Report and Literature Review.

BACKGROUND Acute hemorrhagic leukoencephalitis (AHLE) is a very rare fulminant post-infectious demyelinating disease of the CNS. We report an atypical presentation of AHLE involving unique brain areas 2 weeks following a viral upper-respiratory tract infection (URTI). Early diagnosis and proper management improve the prognosis of this disease, and AHLE can have a very poor prognosis and high mortality rate. CASE REPORT A 52-year-old male patient was referred for deteriorating consciousness 2 weeks after a viral URTI. An initial brain CT scan showed multiple patchy bilateral and diffuse hypodense areas including the cerebellar, occipital, parietal, and frontal lobes. The diagnostic workup also included CSF analysis and MRI of the brain, which revealed multiple areas of hemorrhagic involvement. Management included broad-spectrum antibiotics, acyclovir, mannitol, steroids, and plasmapheresis. On the fifth day of admission, brain CT showed severe diffuse edema and brain herniation. Unfortunately, despite prompt aggressive treatment measures, within 48 hours the patient died due to centrally-mediated hemodynamic instability. CONCLUSIONS We report a rare case of AHLE with a unique presentation and extensive unusual involvement of regions of periventricular and subcortical white matter, cerebellum, and midbrain. Early diagnosis along with appropriate management measures and intensive care can help decrease morbidity and mortality; therefore, prompt referral and high-level care should be sought for all patients who present with acute deteriorating consciousness. We hope that this report can help future studies to better characterize this rare disease and provide further guidance regarding prognosis and management.

Acute Severe Hyponatremia following Hysteroscopic Procedure in a Young Patient: A Case Report and Review of the Literature.

BACKGROUND: Hysteroscopic surgery is a minimally invasive procedure used to diagnose and treat intrauterine pathologies. It requires distension of the uterine cavity for the adequate visualization of the operative field. Glycine (1.5%) is one of the most commonly used solutions because it is nonconductive and also has good optical properties. However, acute hyponatremia is a critical complication that can develop after the absorption of a sufficient amount of the irrigation medium. Case Presentation. We report a case of a 43-year-old female patient who developed acute symptomatic hyponatremia (104 mEq/L) and pulmonary edema secondary to hysteroscopic resection of leiomyoma and hastily approached with rapid sodium correction measures. CONCLUSION: Multiple strategies can be taken to reduce the risk of fluid absorption and subsequent hyponatremia. Moreover, attention should be paid to the treatment approach for patients with acute hyponatremia following hysteroscopic procedures; rapid correction of acute hyponatremia for such patients might be safe, although there is no consensus in the literature, and further trials are needed.

Clinical pearls in hospital nephrology.

Hospitalized patients who have established kidney disease and those who have acute kidney injury in the hospital, along with patients with electrolyte disturbances tend to be some of the most complex to care for. Through working closely in nephrology consultation in the hospital with patients and providers, in both private and academic settings, we have come to encounter certain common presentations and recurrent themes that are worthy of emphasis, and of which a good understanding can translate into improved patient care. For the provider who works closely with such patients, many of these aspects are important to recognize and understand. In this review, we present 10 questions that address some of the highly relevant aspects of nephrology for the provider in the hospital. Through a MEDLINE database search, we reviewed the most pertinent studies as we then go through the explanation of management decisions in an evidence-based methodology with an up-to-date approach based on the current literature on the subject.

Scleroderma Renal Crisis in a Case of Mixed Connective Tissue Disease Treated Successfully with Angiotensin-Converting Enzyme Inhibitors.

Mixed connective tissue disease (MCTD) is a rheumatic disease syndrome with overlapping features of scleroderma, systemic lupus erythematosus, and polymyositis. An extremely rare but serious complication that can occur in MCTD is scleroderma renal crisis (SRC). There have been different approaches to the treatment of SRC associated with MCTD. We present a case of MCTD with chronic features of Raynaud's phenomenon, dermatomyositis, and thrombocytopenia complicated with acute SRC which showed a great response to ACE inhibitors. Here, we advise the early and aggressive use of ACE inhibitors as soon as SRC is suspected.

Predialysis nephrology care amongst Palestinian hemodialysis patients and its impact on initial vascular access type.

Referral time for end-stage renal disease (ESRD) patients to nephrologists and initial vascular access method are considered significant factors that impact health outcomes at the time of hemodialysis (HD) initiation. Native arteriovenous fistula (AVF) is strongly recommended as initial access. However, little is known about the referral rate among ESRD receiving HD in Palestine and its correlation with AVF creation. In Ramallah Hemodialysis Center, we investigated the pre-dialysis nephrology care and AVF usage in 156 patients. Type of access at HD initiation was temporary central venous catheter (CVC) in 114 (73%), tunneled hemodialysis catheter (TDC) in 21 (13%) and AVF in 21 (13%). Out of all participants, 120 (77%) were seen by nephrologist prior to dialysis. Of the participants who initiated dialysis with a CVC, 36 (31%) had not received prior nephrology care. All participants who initiated dialysis with functional AVF had received prior nephrology care. Patients who were not seen by a nephrologist prior to HD initiation had no chance at starting HD with AVF, whereas 17% of those who had nephrology care >12 months started with AVF. In conclusion, a relatively large percentage of Palestinian HD patients who were maintained on HD did not have any predialysis nephrology care. In addition, patients who received predialysis nephrology care were significantly more likely to start their HD through AVF whereas all those without predialysis nephrology care started through CVC. More in-depth national studies focusing on improving nephrology referral in ESRD patients are needed to increase AVF utilization.

Perceived barriers and attitudes toward arteriovenous fistula creation and use in hemodialysis patients in Palestine.

In the dialysis center in Ramallah, we investigated the attitudes and perceived barriers to having arteriovenous fistula (AVF) in 156 patients. The current method of HD access was AVF in 52% and central venous catheter in 47%. Perceived causes of no or delayed AVF were: patient's refusal of AVF in 54.5%, late referral to a surgical evaluation in 31.3% and too long to surgical appointments in 14.2%. Among those who refused AVF, reasons were: concern about the surgical procedure in 42.5%, poor understanding of disease/access in 23.3%, fear of needles in 15.1%, denial of disease or need for HD in 17.8%, and cosmetic reasons in 1.4%. Forty six percent of patients believed they received education about AVF prior to the creation of HD access, and 73.7% would recommend AVF as the method of access due to the lower risk of infection (96%), easier to care for (16%), easier showering (14%), and better-associated hygiene (3%). In conclusion, the majority would recommend an AVF as the mode of vascular access for HD. The most common barrier to having an AVF was patient's refusal to undergo AVF creation because of their concern about the surgical procedure. A systematic evaluation of the process that precedes the creation of AVF may allow for better utilization.

Predialysis nephrology care and its impact on initial vascular access type in hemodialysis patients in Jordan.

Chronic kidney disease (CKD) patients who reach end-stage renal disease (ESRD) require early nephrology referral and appropriate vascular access. Arteriovenous fistula (AVF) is the preferred access for hemodialysis (HD). Referral to nephrology of CKD patients starting HD in Jordan and its impact on AVF utilization is unknown. Patients on in-center HD in a large Jordan Ministry of Health dialysis unit were interviewed, and medical records reviewed to assess prior nephrology care and AVF use. Of 104 total patients, 93 met the inclusion criteria. The mean age was 50 ± 16 years, with 44% being females. The average body mass index was 25 ± 5. The cause of ESRD was diabetes mellitus in 28 (30%), hypertension in 28 (30%), and polycystic kidney disease in three (3%). Type of HD access at the initiation of dialysis was central venous catheter (CVC) in 80 (86%) and AVF in 12 (13%). Of the overall group, 50 (54%) were seen by nephrology before initiating dialysis, and of these, 39 patients (78%) were seen >1 year before HD initiation. Of the patients who initiated dialysis with a CVC, 38 (48%) had received prior nephrology care. All 12 patients who initiated dialysis with AVF had received prior nephrology care. Of the 50 patients who received nephrology care before dialysis initiation, 12 patients (24%) had started dialysis with an AVF; in patients without prior nephrology care, all were started with a CVC. In conclusion, our study suggests that a large percentage did not have nephrology care before initiating dialysis. The ones who were seen by nephrology before dialysis were significantly more likely to initiate dialysis using an AVF. A national focus on improving nephrology referral in advanced CKD may allow better utilization of AVF as the method of access at dialysis initiation.

Bilateral Sustained Nephrograms After Parenteral Administration of Iodinated Contrast Material: A Potential Biomarker for Acute Kidney Injury, Dialysis, and Mortality.

OBJECTIVE: To determine whether persistent bilateral global nephrograms are associated with acute kidney injury (AKI), dialysis, and mortality. PATIENTS AND METHODS: All patients who underwent (1) contrast-enhanced computed tomography (CT) or cardiac catheterization with iohexol between January 1, 2000, and December 31, 2014, and (2) noncontrast abdominal CT in the subsequent 24±6 hours were identified. Patients without preprocedure and postprocedure creatinine measurements or who received additional contrast material were excluded. Nephrograms were identified by radiologist review and CT attenuation measurements. Univariate and multivariate analyses were performed to determine nephrogram risk factors. Acute kidney injury (defined as a creatinine level of ≥0.5 mg/dL or Kidney Disease: Improving Global Outcomes stages 1-3), dialysis, and mortality proportions were compared between patients with and without bilateral global nephrograms using the Fisher's exact test. RESULTS: A total of 123 patients met all inclusion criteria. The proportion of patients with a nephrogram was 37.4% (n=46), with a higher proportion following interventional (67% [18 of 30]) vs diagnostic (27.3% [9 of 33]) catheterization or contrast-enhanced computed tomography (31.7% [19 of 60]). Age (P=.002), chronic kidney disease (P=.05), and acute hypotension or shock (P=.02) were significant risk factors for nephrogram development. Patients with nephrogram had significantly higher rates of AKI (37.0% [17 of 46] vs 5.2% [4 of 77]; odds ratio [OR], 10.7 [95% CI, 3.31-34.5]; P<.001), dialysis (17.4% [8 of 46] vs 1.3% [1 of 77]; OR, 16.0 [95% CI, 1.93-133]; P=.001), and mortality (15.2% [7 of 46] vs 1.3% [1 of 77]; OR, 13.6 [1.62-115]; P=.003) than patients without nephrogram. CONCLUSION: The presence of persistent bilateral global nephrograms suggests an increased risk of AKI, dialysis, and mortality when compared with patients whose kidneys fully eliminated the contrast material.

Cystatin C Predicts Renal Recovery Earlier Than Creatinine Among Patients With Acute Kidney Injury.

INTRODUCTION: Serum cystatin C increases earlier than creatinine during acute kidney injury. However, whether cystatin C decreases earlier during recovery is unknown. This retrospective study aimed to determine the temporal trend between creatinine and cystatin C in acute kidney injury. METHODS: We identified hospitalized patients with nonoliguric acute kidney injury who had serial creatinine and cystatin C values measured between May 2015 and May 2016. Demographic and laboratory data, causes of acute kidney injury, and relevant comorbidity data were collected through chart review. RESULTS: For the 63 identified patients, mean (SD) age was 58.7 (13.9) years; male sex, 62%; white race/ethnicity, 95%. Baseline median (range) creatinine was 1.1 (0.5-3.0) mg/dl; 13% were kidney transplant recipients and 37% received corticosteroids. Comorbidities included malignancy (38%), diabetes mellitus (33%), heart failure (19%), and thyroid disorder (16%). The cause of kidney injury was acute tubular necrosis in 71%, 61% had acute kidney injury stage III, and 33% required dialysis. Cystatin C began to decrease before creatinine in 68% of patients: 1 day earlier, 46%; 2 days earlier, 16%; and 3 days earlier, 6%. In 24% of cases, both began decreasing on the same day; in only 8%, cystatin C decreased after creatinine. Overall, cystatin C mean (95% confidence interval) decrease was 0.92 (0.65-1.18) days before creatinine (P < 0.001). CONCLUSION: In summary, cystatin C decreases before creatinine in most hospitalized patients with acute kidney injury. If confirmed in large prospective studies, these findings may have important management implications, possibly shortening hospital stay and reducing costs.

Impairment of Thyroid Function in Critically Ill Patients in the Intensive Care Units.

Unexplained hypotension in the intensive care unit is commonly attributed to volume depletion, cardiorespiratory failure, sepsis, or relative adrenal insufficiency. In these acute conditions, thyroid hormone levels measured in blood, serum or plasma are often altered and solely attributed to critical illness. We report a series of 3 critically ill patients with prolonged respiratory failure, suppressed mental status and unexplained hypotension. Thyroid stimulating hormone levels ranged from normal to mildly elevated (2.36-7.65IU/mL; normal: 0.27-4.20), but free thyroxin was markedly suppressed (0.239-0.66ng/dL; normal: 0.93-1.70). After initiation of intravenous levothyroxine (75-100µg/day), the patients could be weaned off vasopressors and were successfully extubated shortly thereafter. These cases demonstrate that hypothyroid intensive care unit patients may exhibit even seemingly normal or mildly abnormal thyroid stimulating hormone values. Early recognition and treatment of a hypothyroid state superimposed on critical illness may contribute to recovery from hypotension or the need for mechanical ventilation.

Targeted surgical parathyroidectomy in end-stage renal disease patients and long-term metabolic control: A single-center experience in the current era.

BACKGROUND: The long-term results of surgical parathyroidectomy (PTX) in end-stage renal disease (ESRD) patients are less well known in the modern era of newer activated vitamin-D analogs, calcimimetics and intraoperative monitoring of parathyroid hormone (PTH). METHODS: We performed a retrospective chart review of all ESRD patients undergoing PTX at the University of Mississippi Medical Center between January 2005 and August 2011, with follow-up data as available up to 4 years. All PTXs were performed with intraoperative second-generation PTH monitoring and targeted gland size reduction. RESULTS: The cohort (N = 37) was relatively young with a mean (±SD) age of 48.4 ± 13.9. 94.6% of the subjects were African American and 59.5% female. Preoperatively, 45.9% received cinacalcet (CNC) at a mean dose of 63.5 ± 20.9 mg. The size of the largest removed glands measured 1.7 ± 0.8 cm and almost all (94.6%) glands had hyperplasia on histology. The mean length of inpatient stay was 5.5 ± 2.4 days. Preoperative calcium/phosphorus measured 9.6 ± 1.2/6.6 ± 1.7 mg/dL with PTH concentrations of 1589 ± 827 pg/mL. Postoperative PTH values measured 145.4 ± 119.2 pg/mL. Preoperative PTH strongly correlated (P < 0.0001) with both alkaline phosphatase (ALP) levels (r: 0.596) and the number of inpatient days (r: 0.545), but not with CNC administration. Independent predictors for the duration of hospitalization were preoperative ALP (beta 0.469; P = 0.001) and age (beta -0.401; P = 0.005) (R2 0.45); for postoperative hypocalcemia, age (beta: -0.321; P = 0.006) and preoperative PTH (beta: 0.431; P = 0.036) were significant in linear regression models with stepwise selection. CONCLUSION: Gland-sparing PTX achieved acceptable control of ESRD-associated hyperparathyroidism in most patients from a socioeconomically challenged, underserved population of the United States.

Urinalysis for the diagnosis of glomerulonephritis: role of dysmorphic red blood cells.

Background: Dysmorphic red blood cells (dRBCs) on urine microscopy have been associated with glomerulonephritis (GN). We assessed the prevalence and ability of dRBCs to differentiate GN from other kidney diseases. Methods: Adult patients with kidney biopsy performed between 2012 and 2015 at a single center who had a concurrent urinalysis were retrospectively studied. The association of ≥25% dRBCs with the presence of glomerular pathology was assessed. Univariate and multivariate logistic regression were performed on significantly associated variables. Results: The mean age of the 482 eligible subjects was 55 years and 47.7% were female. Overall, 173 (35.9%) had <25% and 76 (15.8%) had ≥25% urine dRBCs. Kidney biopsies revealed glomerular disease in 372 (77.2%) (GN 46% and non-GN 54%). At the dRBC threshold of ≥25% used at our center, a sensitivity of 20.4%, specificity of 96.3% and positive predictive value of 94.6% for glomerular disease were observed. In a logistic regression model, urine RBCs [>10 versus ≤10 (P < 0.001)] but not dRBCs ≥25% (P = 0.3) independently predicted the presence of GN. A scoring system (0-3) based on hematuria and proteinuria levels revealed the risk for biopsy-proven GN was 15% when the score was 0 compared with 83% when it was 3. Conclusions: The presence of ≥25% urine dRBCs is specific but not sensitive for GN. In this cohort, the combined hematuria (>10 RBCs/high-power field) and proteinuria performed just as well as dRBCs plus proteinuria to predict underlying GN. A model based on the degree of hematuria and proteinuria found on urinalysis was able to predict the presence of GN.