Effects of storage time and temperature on urinary enzymes

Matteucci, Elena; Gregori, Giovanna; Pellegrini, Luisa; Navalesi, Renzo; Giampietro, Ottavio

doi:10.1093/clinchem/37.8.1436

Cited by 22 publications

(5 citation statements)

References 7 publications

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“…At −80°C, enzyme activity was somewhat preserved, although urine GGT activity did start to decline following 14 d of storage. These findings are similar to those reported in human samples, 11 and support the guidance that urine intended for GGT activity studies must not be frozen.…”

Section: Discussionsupporting

confidence: 88%

Validation of a spectrophotometric method for GGT measurement in canine urine and determination of the urine GGT-to-creatinine ratio reference interval and biological variation in 41 healthy dogs

Ilchyshyn¹,

Villiers²,

Monti³

2018

J VET Diagn Invest

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The urine gamma-glutamyl transferase (GGT)-to-creatinine ratio has been used to monitor patients at risk of acute renal injury. We validated the spectrophotometric quantification of GGT in urine in a commercial biochemistry analyzer.The assay was precise, accurate, and linear. Intra-assay precision was 3.59% in 4 samples, with GGT concentrations of 47-195 U/L. Inter-assay precision in 3 samples with activities of 11-51 U/L was 7.74%. Accuracy was 97.3%, with an absolute bias of 2.7 U/L. Urine GGT was unaffected by hematuria, hemoglobinuria, or bacteriuria. Urine GGT was stable at 20°C and 4°C for up to 3 d. Storage by freezing at −20°C resulted in a significant reduction in enzyme activity. A pH outside the range of 6.5-8 resulted in reduced GGT activity. The biological variation of urine GGT-to-creatinine ratio provided an index of individuality of 1.6, indicating that a population-based reference interval (RI) can be used. The reference change value was calculated, and an increase in consecutive measurements >43% is required to be regarded as significant. The urine GGT-tocreatinine ratio RI obtained in a population of 41 healthy dogs was 8.5-28.5 U/g.

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Section: Discussionsupporting

confidence: 88%

Validation of a spectrophotometric method for GGT measurement in canine urine and determination of the urine GGT-to-creatinine ratio reference interval and biological variation in 41 healthy dogs

Ilchyshyn¹,

Villiers²,

Monti³

2018

J VET Diagn Invest

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“…Freezing results in significant reductions in urinary AAP activity, whereas it exerts only a minor effect on the enzyme activity in Sephadexfiltered urine samples (Sephadex G-25 M, Amersham Pharmacia Biotech AB, Upsala, Sweden) (E. Taracha, unpublished data). Similar observations have been reported for other enzymes (Mattenheimer and Maruhn, 1992;Matteucci and Giampietro, 1994;Matteucci et al, 1991). Therefore, in this study urine samples were kept refrigerated at ϩ4°C (for no longer than 3 days) until assayed for AAP activity.…”

Section: Biochemistrysupporting

confidence: 80%

Alanine Aminopeptidase Activity in Urine: A New Marker of Chronic Alcohol Abuse?

Taracha

Habrat

Lehner

et al. 2004

Alcoholism Clin & Exp Res

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“…Research has suggested urine samples should not be frozen for albumin determination and refrigeration does not appear to be necessary ( 11 , 13 ). When samples are stored for 24 hours, storage at room temperature or 4°C does not appear to effect urine enzyme values ( 14 ). Similar to the literature, our findings suggested samples do not need to be refrigerated or frozen if assessed within 48 hours of voiding.…”

Section: Discussionmentioning

confidence: 99%

“…Likewise, limited research is available investigating the effect storage temperature has on urine specimen, none of which concentrates on hydration status. Studies that focused on the impact of storage temperature on albumin determination and urine enzyme values have suggested urine samples should not be frozen and can be stored for 24 hours at room temperature or 4°C without impacting results ( 11 - 14 ).…”

Section: Introductionmentioning

confidence: 99%

Effects of Agitation and Storage Temperature on Measurements of Hydration Status

et al. 2015

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Background:Hypohydration can have significant implications on normal physiological functions of the body.Objectives:This study aimed to determine the impact of agitation, storage temperature, and storage time on urine osmolality compared to the criterion control.Patients and Methods:We used a descriptive diagnostic validity test design. To investigate agitation, we recruited 75 healthy individuals (males = 41, females = 34; mean age = 22 ± 5 years; mean self-reported height = 172 ± 23 cm and mass = 77 ± 17 kg) who provided one or more samples (total = 81). The independent variables were agitation (vortex, hand shaken, no agitation) and temperature (room temperature, freezer, and refrigerator) type. Participants completed informed consent, a health questionnaire and were asked to provide a urine sample, which was split and labeled according to agitation type or storage temperature. Urine osmolality was used to determine hydration status at two time points (within 2 hours [control], 48 hours). We used t-tests to determine the difference between each condition and the control and calculated percent error for each condition.Results:No significant differences for no agitation (t79 = -0.079, P = 0.937), hand shaken (t79 = 1.395, P = 0.167) or vortex mixed (t79 = -0.753, P = 0.453) were identified when compared to the criterion control. No significant differences for room temperature (t82 = -0.720, P = 0.474), refrigerator (t82 = -2.697, P = 0.008) or freezer (t82 = 2.576, P = 0.012) were identified when compared to the criterion control.Conclusions:Our findings suggest agitation of urine specimen is not necessary and samples do not require refrigeration or freezing if assessed within 48 hours. Analysis within two hours of collection is not necessary and samples can be stored for up to 48 hours without impacting the hydration status of the sample.

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Effects of storage time and temperature on urinary enzymes

Cited by 22 publications

References 7 publications

Validation of a spectrophotometric method for GGT measurement in canine urine and determination of the urine GGT-to-creatinine ratio reference interval and biological variation in 41 healthy dogs

Validation of a spectrophotometric method for GGT measurement in canine urine and determination of the urine GGT-to-creatinine ratio reference interval and biological variation in 41 healthy dogs

Alanine Aminopeptidase Activity in Urine: A New Marker of Chronic Alcohol Abuse?

Effects of Agitation and Storage Temperature on Measurements of Hydration Status

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