***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract A prospect i ve study was conducted to determine the correlation of early morning urinary protein/osmolality ratio ( mg/l/mosmol/kg ) with 24-h urinary protein excretion ( mg/m2/day ) . Study patients consisted of 53 children ( aged 1 month to 15 years ) .  Early morning urine sample s and 24-h urine sample s were collected and analyzed . In group 1 ( children without proteinuria ) , early morning urinary protein/creatinine ratio ( Uprot/Ucr , mg/mg ) was 0.061±0.011 and the protein/osmolality ratio ( Uprot/Uosm , mg/l/mosmol/kg ) was 0.073±0.014 . Twenty-four hour urinary protein excretion in group 1 had no significant correlation with Uprot/Ucr or Uprot/Uosm . In group II ( children with proteinuria ) , Uprot/Ucr was 5.78±1.10 and Uprot/Uosm was 4.42±1.34 . Twenty- four hour urinary protein excretion in group 2 was 1483.6±303.7 mg/m2/day and its correlation with both Uprot/Uosm and Uprot/Ucr was highly significant ( r= 0.87 , P<0.001 and r=0.88 , P<0.001 , respectively ) . The accepted nephrotic level of proteinuria of 40 mg/m2/h coincides with a Uprot/Uosm ratio of 1.9 . In conclusion , early morning urinary Uprot/Uosm is a simple and potentially useful test for 24-h urinary protein excretion , and possibly could be used safely for the assessment of the degree of proteinuria in children We examined the relative feasibility of using r and om urinary dipstick testing and urinary protein/creatinine ratios in the quantitation of proteinuria . Sixty-four children with relapsing nephrotic syndrome , ranging in age from 1 1/2 to 16 years , contributed 145 timed urine collection s and 150 r and om specimens  , which were analyzed by urinary protein dipstick , quantitation of protein and creatinine , or both . Total protein excretion was expressed as grams per surface area per day and the urinary protein/creatinine ratio as milligrams of protein per milligram of creatinine . Degrees of proteinuria were design ated as physiologic ( less than 0.1 gm/m2/day ) , intermediate ( greater than 0.1 and less than 1.0 gm/m2/day ) , or nephrotic ( greater than 1.0 gm/m2/day ) . The log regression analysis of the 24-hour urinary protein/creatinine ratio ( y ) and total protein excretion ( x ) was highly significant ( r = 0.97 ; p less than 0.001 ) . The upper and lower confidence limits of the urinary protein/creatinine ratio ( 1.0 and 0.1 , respectively ) closely approximated the design ations for nephrotic and physiologic proteinuria , respectively . These values were therefore used to classify degrees of proteinuria by the urine protein/creatinine ratio . The validity of these tests was assessed by sensitivity , specificity , and predictive value , and compared with that of r and om testing by urinary dipstick . The urinary protein/creatinine ratio offered good reliability as a test for classifying degrees of proteinuria and accurately predicting nephrotic and physiologic proteinuria . The r and om dipstick testing was reliable only when results were distinctly positive and when sensitivity and specificity were low . The error in the total protein excretion value that was imposed by collection errors with high and low variations in the creatinine value ( 57 % of sample s ) was largely corrected by normalization of the data by log transformation . When controlled for creatinine excretion , linear regression analysis allowed calculation of total protein excretion ( TP ) from the urinary protein/creatinine ratio ( U P/Cr ) by the following equation : TP ( gm/m2/day ) = 0.63 ( U P/Cr ) at all levels of proteinuria . The r and om urinary protein/creatinine ratio appeared to offer the most sensitive test for classification of proteinuria in children with nephrosis , with the advantages of ease and expediency not afforded by the 24-hour urine quantitation OBJECTIVES To determine the correlation between the protein/creatinine ratio and 24-h proteinuria ; to estimate the sensitivity and specificity of this ratio for the diagnosis of significant proteinuria ; to establish its cutoff point with the best predictive value for the diagnosis of significant proteinuria in patients with systemic arterial hypertension . STUDY DESIGN A cross-sectional study of 47 hypertensive patients who had been pregnant for 20 weeks or more seen at the Maternity of the University Hospital of Porto Alegre . The studied factor was the protein/creatinine ratio measured in a single r and om urine sample and the outcome was  protein determination in 24-h urine . The level of significance was set at 0.05 . RESULTS The correlation coefficient between the protein/creatinine ratio and 24-h proteinuria was 0.94 when urine was properly collected . A receiver-operator characteristic curve was constructed to determine the sensitivity and specificity of the ratio for the diagnosis of significant proteinuria ( > or = 300 mg in 24 h ) . Specificity and predictive positive value were 100 % for a ratio > or = 0.8 . The best values for sensitivity , specificity , positive predictive value , and negative predictive value in the diagnosis of proteinuria > or = 300 mg in 24 h were obtained when the protein/creatinine ratio was 0.5 ( 0.96 , 0.96 , 0.96 , and 0.96 , respectively ) . CONCLUSION The protein/creatinine ratio measured in a single urine sample taken at r and om from hypertensive pregnant women showed good sensitivity and specificity for the diagnosis of 24-h proteinuria > or = 300 mg and was strongly correlated with 24-h proteinuria . A ratio of 0.5 mg/mg is predictive of significant proteinuria and can be used for the diagnosis and follow-up of hypertensive pregnant women The albumin to creatinine ratio ( ACR ) can be used to measure urine albumin excretion rates , but is inconvenient and expensive . More rapid and less expensive screening methods estimate only albumin concentration and are subject to errors caused by variation in urine volume . We examined whether urine specific gravity could be used in place of urine creatinine to correct albumin concentration for differences in urine volume in 50 patients . Urine specific gravity accurately estimated urine creatinine concentration ( r = 0.79 , P < 0.001 ) . The  albumin estimated-creatinine ratio ( ACestR ) in r and om spot urine sample correlated with urine albumin excretion measured in a 24-hour urine collection ( r = 0.98 , P < 0.001 ) , as did the ACR ( r = 0.95 , P < 0.001 ) . For determining microalbuminuria , the sensitivity ( 0.88 ) and specificity ( 0.93 ) of the ACestR were similar to those of ACR ( 0.89 and 0.93 , respectively ) . Unfortunately , the sensitivity ( 0.63 ) of the Micral-Test was relatively poor , and was only slightly improved by correcting for urine specific gravity ( 0.69 ) in this small sample of patients . Nevertheless , these results suggest that as rapid methods for measuring urine albumin concentration improve , combining them with urine specific gravity might produce a less expensive and more convenient alternative to the ACR abstract Objective : To evaluate whether the protein : creatinine ratio in spot morning urine sample s is a reliable indicator of 24 hour urinary protein excretion and predicts the rate of decline of glomerular filtration rate and progression to end stage renal failure in non-diabetic patients with chronic nephropathy . Design : Cross sectional correlation between the ratio and urinary protein excretion rate . Univariate and multivariate analysis of baseline predictors , including the ratio and 24 hour urinary protein , of decline in glomerular filtration rate and end stage renal failure in the long term . Setting : Research centre in Italy . Subjects : 177 non-diabetic out patients with chronic renal disease screened for participation in the ramipril efficacy in nephropathy study . Main outcome measures : Rate of decline in filtration rate evaluated by repeated measurements of unlabelled iohexol  plasma clearance and rate of progression to renal failure . Results : Protein : creatinine ratio was significantly correlated with absolute and log transformed 24 hour urinary protein values ( P=0.0001 and P<0.0001 , respectively . ) Ratios also had high predictive value for rate of decline of the glomerular filtration rate ( univariate P=0.0003 , multivariate P=0.004 ) and end stage renal failure ( P=0.002 and P=0.04 ) . Baseline protein : creatinine ratios and rate of decline of the glomerular filtration rate were also significantly correlated ( P<0.0005 ) . In the lowest third of the protein : creatinine ratio ( < 1.7 ) there was 3 % renal failure compared with 21.2 % in the highest third ( > 2.7 ) ( P<0.05 ) . Conclusions : Protein : creatinine ratio in spot morning urine sample s is a precise indicator of proteinuria and a reliable predictor of progression of disease in non-diabetic patients with chronic nephropathies and represents a simple and inexpensive procedure in establishing severity of renal disease and prognosis . Key messages The protein : creatinine ratio measured in spot morning urine sample s is a simple and reliable indicator of 24 hour urinary protein excretion rate and can therefore be used to quantify proteinuria without the need for timed urine collection Spot morning urinary protein : creatinine ratio is the strongest baseline predictor of progression of renal disease in non-diabetic patients with chronic nephropathies Compared with 24 hour urinary protein excretion rate , the spot morning ratio is an even more reliable predictor of decline in glomerular filtration rate and progression to end stage renal failure and represents a simple and inexpensive procedure in the determination of severity of renal disease and The protein creatinine index in early morning and r and om urine specimens was compared with the 24 hour urinary excretion of protein in normal subjects and out patients with abnormal proteinuria . A protein creatinine index ( defined as ( mg protein/1 divided by creatinine mmol/1 ) times 10 ) below 125 in a r and om specimen excluded abnormal proteinuria , whereas an index of more than 136 indicated the presence of pathological proteinuria . The index for r and om specimens provided a useful semiquantitative assessment of the 24 hour excretion of protein ( mg protein/24 hours ) , but the index for early morning specimens was less reliable . Errors with Albustix were partly due to intra and inter observer variations in the interpretation of the colour formed when compared with the chart provided . It is proposed that the protein creatinine index on r and om urine sample s should be used to supplement dipsticks in screening for proteinuria in cases where misclassification would be serious OBJECTIVE The purpose of this study was to determine the value of the protein/creatinine ratio in prediction of 24-hour urine total protein among women with suspected preeclampsia . STUDY DESIGN Women who were evaluated for suspected preeclampsia at > or=24 weeks of gestation were studied prospect ively if there was no concurrent diagnosis of chronic hypertension , diabetes mellitus , or preexisting renal disease . A protein/creatinine ratio was obtained , which was followed by the initiation of a 24-hour urine evaluation . Positive and negative predictive values and sensitivity and specificity of the protein/creatinine ratio for significant ( > or=300 mg ) and severe proteinuria ( > or=5000 mg ) that were based on 24-hour urine total protein were calculated . RESULTS A total of 220 women were evaluated ; 43.2 % of the women were black , and 80 % of the women had government insurance . Mean maternal and gestational ages were 26.1 years and 36.5 weeks , respectively .  Significant and severe proteinuria on 24-hour urine evaluation were identified in 76.4 % and 8.2 % of cases , respectively . Regression analysis of protein/creatinine ratio and 24-hour urine total protein level showed a poor correlation ( r(2)=0.41 ) . Receiver operator characteristic analysis revealed an area under the curve of 0.80 , but the shoulder value of 390 mg/g carried a high false-negative rate ( 45.2 % ) . With a more conservative cutoff value , a protein/creatinine ratio of > or=300 mg/g had a poor negative predictive value ( 47.5 % ) , a specificity for significant proteinuria ( 55.8 % ) , with a positive predictive value of 85.5 % , and a sensitivity of 81 % . For severe proteinuria , a protein/creatinine ratio of > or=5000 mg/g had a poor positive predictive value ( 61.9 % ) and sensitivity ( 72.2 % ) , with a negative predictive value of 97.5 % , and a specificity of 96.0 % . CONCLUSION Protein/creatinine ratio does not exclude adequately the presence of significant proteinuria or predict severe proteinuria and should not be used as an alternative to 24-hour total protein evaluation AIM A prospect i ve cross-sectional study was performed on 170 patients with various glomerular diseases to study the accuracy of predicting 24-hour proteinuria from the spot urine protein-creatinine ratio ( Up/U 
    Output:
    
The protein : creatinine ratio on a r and om urine specimen provides evidence to " rule out " the presence of significant proteinuria as defined by a 24-h urine excretion measurement