Screening for proteinuria in a rheumatology clinic: comparison of dipstick testing, 24 hour urine quantitative protein, and protein/creatinine ratio in random urine samples.

Abstract

GlasgowSUMMARY Measurements of protein/creatinine ratio in 'spot' urine samples were compared with measurements of 24 hour quantitative proteinuria and side room 'dipstick' testing in 104 samples from 90 patients presenting consecutively to a rheumatology unit. Linear regression analysis showed a highly significant correlation between the random urinary protein/creatinine ratio and total protein excretion in 24 hour urine samples (r=0.92, p<0.001, y=6-55x+0-04). Although an approximation of 24 hour urinary protein excretion could have been made from the regression line: 24 hour urine protein=6-55 xprotein/creatinine ratio+0*04 (g/l), there was a wide scatter of values, particularly in patients with >1 g/24 h urinary protein excretion. Nevertheless, significant proteinuria (>300 mg/24 h) could have been confirmed or excluded with a sensitivity and specificity of 97% by adopting random protein/creatinine values of <0-04 as 'normal'. Specificity and sensitivity could have been increased to 100%, however, by excluding patients with values lying between 0*01 and 0-10 as all the false negatives (n=3) and false positives (n=3) lay within this range. In comparison, dipstick testing, although 100% sensitive, had a poor specificity due to the high false positive rate (40/83 (48%)) in patients with 1+ to 3+ readings. Assessment of random urinary protein/creatinine ratio may obviate the need for 24 hour urine collections in the initial assessment of suspected proteinuria. A wider application of this technique seems indicated in view of the obvious advantages in terms of cost, time, and patient convenience.Screening for proteinuria is a common requirement in rheumatological practice, particularly in patients who are receiving second line agents such as gold and penicillamine. In current clinical practice it is usual to screen for proteinuria by dipstick testing, and when a positive result is obtained to confirm or refute the presence of proteinuria by a 24 hour collection.1 As 24 hour urine collections are laborious, costly, and inconvenient the present study was designed to see if the 24 hour urinary protein excretion could be assessed accurately from the protein/creatinine ratio in random urine samples-a method which has previously been shown to corre-

Elevation of Urinary Adipsin in Preeclampsia

“…However, many studies have reported a poor correlation between the dipstick examination and the 24-hour urine assay with high false-positive or false-negative rates. 11,12 We aimed to find a urine protein in preeclampsia that closely correlated with the 24-hour urine protein and was at a Abstract-Early diagnosis and treatment of preeclampsia are essential for prevention of seizure development and fetus maturation. Although various methods have been developed for predicting or monitoring the onset of preeclampsia, a simple assay that can be used as a home or point of care test remains unavailable.…”

“…However, many studies have reported a poor correlation between the dipstick examination and the 24-hour urine assay with high false-positive or false-negative rates. 11,12 We aimed to find a urine protein in preeclampsia that closely correlated with the 24-hour urine protein and was at a concentration range allowing the development of a rapid laminar flow immunoassay. This rapid test should be sensitive and specific for the preeclampsia diagnosis and can be easily used by both patients and healthcare providers.…”

Proteinuria and metabolic syndrome as predictors of cardiovascular death in non-diabetic and type 2 diabetic men and women

“…A methodological limitation of our study is that at the baseline examination, performed more than 20 years ago, we measured total urinary protein concentration from spot urine samples with the Coomassie brilliant blue method, instead of using a specific assay for albumin [46][47][48] which constitutes about one-half of total urinary protein [49]. Correlation of albuminuria with proteinuria has been previously documented with convergence toward the line of unity with increasing degrees of proteinuria [50].…”

A patient with juvenile chronic arthritis and Henoch-Schönlein purpura

“…10 Screening for proteinuria is a common requirement in rheumatological practice, particularly in patients who are receiving second-line drugs. 11 The use of the urine protein:creatinine ratio rather than the 24-h excretion was also of practical value in monitoring the effects of drug therapy in this group of patients. Collection of a random, rather than a 24-h, urine is more convenient and avoids errors due to incomplete urine collection.…”