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Purpose Loss of muscle mass and strength are associated with long‐term adverse health outcomes in older adults. Urine creatinine concentrations (Ucr; mg/dl) are a measure of muscle tissue mass and turnover. This study assessed the associations of a spot Ucr level with muscle mass and with risk of hospitalization, mortality, and diabetes mellitus in older adults. Methods: We examined 3424 participants from the Cardiovascular Health Study who provided spot urine samples in 1996–1997 and who were followed through June 2015. All participants underwent baseline measurement of grip strength. In a sub‐cohort, 1331 participants underwent dual energy X‐ray absorptiometry (DEXA) scans, from which lean muscle mass was derived. Participants were followed for a median of 10 years for hospitalizations and mortality, and 9 years for diabetes mellitus. Results: In linear regression analysis, a one standard deviation higher Ucr concentration (64.6 mg/dl) was associated with greater grip strength (kg force) β = 0.44 [0.16, 0.72]; p = 0.002) and higher lean muscle mass (kg) (β = 0.43 [0.08, 0.78]; p = 0.02). In Cox regression analyses, each standard deviation greater Ucr concentration was associated with lower rates of hospitalizations (0.94 [95% confidence interval, 0.90, 0.98]; p < 0.001) and lower mortality risk (0.92 [0.88, 0.97]; p < 0.001), while a one standard deviation increase in muscle mass derived from DEXA had no such significant association. Ucr levels were not associated with incident diabetes mellitus risk (0.97 [0.85, 1.11]; p = 0.65). Conclusion: A higher spot Ucr concentration was favorably associated with muscle mass and strength and with health outcomes in older community‐living adults. The ease of obtaining a spot Ucr makes it an attractive analyte to use for gauging the health of older adults. [ABSTRACT FROM AUTHOR]

Background: Serum creatinine concentrations are higher in Greyhounds when compared with nonsighthound breeds. Greyhounds might also have higher urine creatinine concentrations compared with other breeds, which could affect urine protein‐to‐creatinine ratio (UPC) references. Objectives: We aimed to determine the UPC reference intervals (RIs) in healthy nonracing Greyhounds and compare this with UPC values in a group of healthy nonsighthounds and with the current International Renal Interest Society (IRIS) guidelines. Methods: The study used an observational cross‐sectional design, involving clinically healthy, nonracing Greyhounds (n = 98) and nonsighthound dogs of similar weight, age, and sex (n = 24). Packed cell volumes, total solids, urine protein concentrations, serum and urine creatinine concentrations, urine specific gravity (USG) measurements, and UPCs were determined. Linear regression was used to compare urine creatinine and urine protein concentrations, relative to the USG measurements, between Greyhound and nonsighthound groups. Greyhound UPC RIs were determined using nonparametric methods and compared with UPC values in nonsighthounds and current IRIS guidelines. Results: Mean urine creatinine concentrations, adjusted for USGs, were approximately 22% higher in Greyhounds compared with nonsighthounds (P =.002). Mean urine protein concentration (P =.46) and UPC (P =.1) were not significantly different between Greyhounds and nonsighthounds. The upper limit of the Greyhound UPC RI was 0.20 or 0.42, depending on whether strict or moderate exclusion criteria were applied, respectively. Conclusions: Greyhounds have higher urine creatinine concentrations than nonsighthounds. Although the suggested RI for UPCs in Greyhounds is slightly lower than the cut‐offs recommended in generic canine IRIS guidelines, this difference is not likely to be clinically significant. [ABSTRACT FROM AUTHOR]

Background: Urine concentration (UC) provides clinically useful information concerning hydration status and renal function of animals. Objectives: To characterize the clinical performance of urine specific gravity measured by optical refractometry (USG‐R) or Multistix‐SG urine reagent dipstick (USG‐D), urine electrical conductivity using an OAKTON Con 6 conductivity handheld meter (UEC), urine color (UColor) using a custom‐designed 8‐point color chart, and urine creatinine concentration (UCreat) for assessing UC in dairy cattle. Animals: 20 periparturient Holstein‐Friesian cows. Methods: Urine was obtained by perineal stimulation or urethral catheterization and urine osmolality (UOsm, reference method), USG‐R, USG‐D, UEC, UColor, and UCreat determined. Diagnostic test performance was evaluated using Spearman's rho and logistic regression to determine the area under the receiver operating curve (AUC) and optimal cut point for diagnosing hypohydration (UOsm ≥800 mOsm/kg). P < .05 was considered significant. Results: The best performing test for diagnosing hypohydration was USG‐R (AUC = 0.90) at an optimal cut point ≥1.030. The second‐best performing test was UEC (AUC = 0.82) at a cut point of ≥23.7 mS/cm, followed by UCreat (AUC = 0.76) at a cut point of ≥95.3 mg/dL, and UColor (AUC = 0.74) at a cut point of ≥4 on an 8‐point scale. Urine specific gravity measured by dipstick performed poorly (AUC = 0.63). Conclusions and Clinical Importance: USG‐R and UEC provide practical and sufficiently accurate methods for measuring UC in dairy cattle. Urine color had moderate clinical utility as a no‐cost cow‐side method for assessing UC, whereas dipstick refractometry is not recommended for assessing UC. [ABSTRACT FROM AUTHOR]

Examines the benefits of urinary methylmalonic acid (MMA) and creatinine for cobalamin (Cbl) deficiency diagnosis. Usage of gas chromatography mass spectrometry; Sensitivity of MMA tests with functional tissue Cbl assessment; Interrelation between MMA levels and Cbl-dependent metabolic pathway.