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Karl E. Luke

Bio: Karl E. Luke is an academic researcher from Bayer Corporation. The author has contributed to research in topics: Dipstick & Microalbuminuria. The author has an hindex of 3, co-authored 3 publications receiving 74 citations.

Papers
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Journal ArticleDOI
TL;DR: The albumin/creatinine ratio from the Bayer dipsticks gave better accuracy for albumin excretion than the albumin pads alone from either manufacturer.
Abstract: Three hospital sites evaluated the Bayer two-pad urine dipstick as a screening test for microalbuminuria One pad estimates albumin concentrations between 10 and 150 mg/L, and the second estimates creatinine values between 300 and 3,000 mg/L The Boehringer Mannheim (BMD) Micral dipstick was also compared and evaluated The accuracy of the dipsticks was judged by comparison with cuvet-based immunonephelometry for albumin and to standard rate-Jaffe methods for creatinine; these assays were well standardized and controlled and were assumed to give accurate values Precision of these methods and that of the dipsticks was determined by multiple assays of control materials Visual or instrument (Clinitek 50 or 100) evaluation of the Bayer or visual checks of the BMD albumin dipstick pad with patients' urines gave clinically acceptable accuracy The albumin/creatinine ratio from the Bayer dipsticks gave better accuracy for albumin excretion than the albumin pads alone from either manufacturer This ratio should permit making a good estimate of the 24-hr albumin excretion in a randomly collected urine

30 citations

Journal ArticleDOI
TL;DR: A multisite evaluation of a new urine dipstick called Multistix PRO™ (Bayer, Elkhart, IN), which has reagent pads for the simultaneous assay of urinary albumin, protein, and creatinine found that dividing the dipsticks’ albumin or protein results by the creatInine concentration reduced the number of false‐positive album in or protein values observed in concentrated urines, and reduced theNumber of false negatives in dilute urines.
Abstract: The goal of our study was to perform a multisite evaluation of a new urine dipstick called Multistix PROtrade mark (Bayer, Elkhart, IN), which has reagent pads for the simultaneous assay of urinary albumin, protein, and creatinine. Patients' urine specimens were assayed at four sites with these dipsticks and with the familiar Bayer Multistix 10SG dipsticks for protein. The new dipstick pads for albumin are impregnated with bis (3',3"-diiodo-4',4"-dihydroxy-5',5"-dinitrophenyl)-3,4,5,6-tetrabromo-sulfonephthalein (DIDNTB) dye. These dipsticks also have a novel pad that estimates urinary creatinine using the peroxidase activity of the copper-creatinine complex. We determined the interlaboratory agreement of these dipsticks by comparing dipstick results to values obtained by quantitative analytical methods. We found that dividing the dipsticks' albumin or protein results by the creatinine concentration reduced the number of false-positive albumin or protein values observed in concentrated urines, and reduced the number of false negatives in dilute urines. The ratio of albumin to creatinine, or protein to creatinine gives a better measure of albumin or protein excretion. Compared to reading by eye, the dipstick results agreed better with the quantitative assays when they were read by a reflectometer (Bayer Clinitek).

26 citations

Journal ArticleDOI
TL;DR: Patients with cardiovascular disease, kidney disease, or diabetes showed the greatest predictive value of a positive test for albumin or protein by dipstick, suggesting that albuminuria and/or proteinuria were underdiagnosed in this group of patients.
Abstract: We tested patients’ urines for albumin, protein, and creatinine by quantitative and dipstick methods. The concentrations of these analytes were established by quantitative, cuvet-based chemistry methods that we assumed gave the “correct” values. There was good to excellent agreement of the dipstick results with the quantitative methods for the above three analytes. We found many patients who excreted pathological amounts of albumin and/or protein who did not have a diagnosis of kidney disease or other likely causes of proteinuria, suggesting that albuminuria and/or proteinuria were underdiagnosed in our group of patients. Those with cardiovascular disease, kidney disease, or diabetes showed the greatest predictive value of a positive test for albumin or protein by dipstick. Dipstick testing for albumin, protein, and creatinine had good or excellent agreement with quantitative methods. The dipstick tests were easy to use, simple, and low in cost, and can serve well for point-of-care testing. J. Clin. Lab. Anal. 15:295–300, 2001. © 2001 Wiley-Liss, Inc.

19 citations


Cited by
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Journal ArticleDOI
TL;DR: Pooled analysis of data obtained from a population of hyperlipidemic patients enrolled in the rosuvastatin (Crestor®) clinical development program permitted assessment of its effects on renal function both early and later in the course of treatment, suggesting that rosuVastatin may arrest the progression of renal disease.
Abstract: Preclinical and limited clinical data suggest that statins decrease the progressive decline in renal function that occurs in patients with renal disease. Pooled analysis of data obtained from a population of hyperlipidemic patients enrolled in the rosuvastatin (Crestor) clinical development program permitted assessment of its effects on renal function both early and later in the course of treatment. Study participants were initially included in controlled clinical trials that evaluated the lipid-lowering efficacy and safety of rosuvastatin when compared with placebo or other lipid-lowering agents (i.e., atorvastatin, simvastatin, pravastatin, cholestyramine, fenofibrate or extended-release niacin). The median duration of treatment with the various doses of statins in these trials was approximately 8 weeks. Following completion of a controlled clinical trial, patients were permitted to enter an open-label extension trial and received rosuvastatin treatment. These data permitted assessment of renal function in a diverse group of over 10,000 patients who received rosuvastatin in its recommended dose range (5-40 mg) for up to 3.8 years. Mean serum creatinine concentrations were lower when compared with baseline both early and later in the course of rosuvastatin treatment. In contrast, no change in mean serum creatinine was observed with placebo. Mean glomerular filtration rates (GFR) predicted from the Modification of Diet in Renal Disease (MDRD) equation were higher when compared with baseline both early and later in the course of rosuvastatin treatment. No change in GFR was observed in the placebo group. Among patients who received long-term rosuvastatin treatment (> or =96 weeks), GFR was unchanged or tended to increase, rather than decrease, when compared with baseline irrespective of age, gender, hypertensive or diabetic status, level of renal function (GFR > or =60 vs. <60 ml/min/1.73 m(2)) at entry or urine dipstick protein status prior to or during the period of treatment. These findings suggest that rosuvastatin may arrest the progression of renal disease.

156 citations

Journal ArticleDOI
TL;DR: A dipstick test plus an optical strip reader that can measure urine protein, albumin, and creatinine and calculate the appropriate ratios provides a better screening test for albuminuria or proteinuria than one measuring only albumin or protein.

149 citations

Book
01 Jan 2011
TL;DR: Generating and Interpreting Test Results: Test Validity, Quality Control, Reference Values, and Basic Epidemiology.
Abstract: Contributing Authors. Preface. Acknowledgments. Chapter 1. Erythrocytes. Chapter 2. Leukocytes. Chapter 3. Hematopoietic Neoplasia. Chapter 4. Hemostasis. Chapter 5. Water, Electrolytes, and Acid Base. Chapter 6. Proteins, Lipids, and Carbohydrates. Chapter 7. Liver. Chapter 8. Digestive System. Chapter 9. Urinary System. Chapter 10. Muscle. Chapter 11. Endocrine System. Chapter 12. Cytology. Chapter 13. Generating and Interpreting Test Results: Test Validity, Quality Control, Reference Values, and Basic Epidemiology. Case Studies. Index.

146 citations

Journal ArticleDOI
TL;DR: As a first step towards a fully disposable stand-alone diagnostic microchip for determination of urinary human serum albumin (HSA), the use of a thin-film organic light emitting diode (OLED) as an excitation source for microscale fluorescence detection is reported.
Abstract: As a first step towards a fully disposable stand-alone diagnostic microchip for determination of urinary human serum albumin (HSA), we report the use of a thin-film organic light emitting diode (OLED) as an excitation source for microscale fluorescence detection. The OLED has a peak emission wavelength of 540 nm, is simple to fabricate on flexible or rigid substrates, and operates at drive voltages below 10 V. In a fluorescence assay, HSA is reacted with Albumin Blue 580, generating a strong emission at 620 nm when excited with the OLED. Filter-less discrimination between excitation light and generated fluorescence is achieved through an orthogonal detection geometry. When the assay is performed in 800 µm deep and 800 µm wide microchannels on a poly(dimethylsiloxane) (PDMS) microchip at flow rates of 20 µL min−1, HSA concentrations down to 10 mg L−1 can be detected with a linear range from 10 to 100 mg L−1. This sensitivity is sufficient for the determination of microalbuminuria (MAU), an increased urinary albumin excretion indicative of renal disease (clinical cut-off levels: 15–40 mg L−1)

96 citations

Journal ArticleDOI
TL;DR: Using the KDIGO guidelines in a correct way, "kidney damage" (confirmed proteinuria, hematuria) and the demonstration of chronicity of decreased eGFR <60 ml/min/1.73 m(2), combined with the third percentile as a cutoff for the normality of eG FR for age and sex, overcome false positives and negatives, substantially decrease CKD3A prevalence, and greatly increase the accuracy of identifying CKD.

88 citations