Paula Vega Guerrero - Academia.edu (original) (raw)
Papers by Paula Vega Guerrero
Annals of clinical and laboratory science, 2021
Journal of clinical laboratory analysis, 2016
The goal of this work was to determine whether there are clinically significant fluctuations in t... more The goal of this work was to determine whether there are clinically significant fluctuations in the level of serum creatinine on serial determinations, especially in the borderline range (1.1-1.3 mg/dl), after specimen storage. Sixty-one serum samples were analyzed. They were divided into three categories based on the initial serum creatinine measurement: low (≤1.0 mg/dl), borderline (1.1-1.3 mg/dl), and high (≥1.4 mg/dl). The specimens were stored at 4°C and run on the Siemens Advia 1800 chemistry analyzer on days 1, 3, and 11. Statistical comparisons of the three groups were made using the unpaired t-test, yielding a two-tailed P-value for each group comparison. The P-values ranged from 0.0829 to 0.3892, indicating no statistically significant difference between the standard deviations of each group. Mild-to-moderate fluctuations in precision occur in successive serum creatinine determinations. The overwhelming majority of these fluctuations should not affect clinical decision mak...
Journal of clinical laboratory analysis, Jan 13, 2015
The goal of this work was to determine if immediate versus postponed centrifugation of samples af... more The goal of this work was to determine if immediate versus postponed centrifugation of samples affects the levels of serum potassium. Twenty participants donated normal venous blood that was collected in four serum separator tubes per donor, each of which was analyzed at 0, 1, 2, or 4 hr on the Siemens Advia 1800 autoanalyzer. Coefficients of variation (CVs) for potassium levels ranged from 0% to 7.6% with a mean of 3 ± 2%. ANOVA testing of the means for all 20 samples showed a P-value of 0.72 (>0.05) indicating that there was no statistically significant difference between the means of the samples at the four time points. Sixteen samples were found to have CVs that were ≤5%. Two samples showed increases of potassium from the reference range to levels higher than the upper reference limit, one of which had a 4-hr value that was within the reference or normal range (3.5-5 mEq/l). Overall, most samples were found to have reproducible levels of serum potassium. Serum potassium level...
Annals of clinical and laboratory science, 2013
Because of the metabolism of serum glucose in collection tubes containing blood samples, serum gl... more Because of the metabolism of serum glucose in collection tubes containing blood samples, serum glucose levels may be found to decrease over time. Several types of collection tubes have been designed to, at least partially, block glucose metabolism by red blood cells in blood collection tubes that may not be analyzed immediately after blood collection. These include red-top collection tubes with serum separator, grey-top tubes with a fluoride glycolysis inhibitor, and heparin-containing green-top tubes which prevent clot formation. As part of a quality assurance project, we investigated whether glucose levels differed in the three tube types from each of 18 volunteers on a prolonged standing of 4 hours. We then determined the glucose concentrations of all three tubes from each of the 18 volunteers. We used refrigerated samples over a five-day period to determine if the initial values were reproducible. Surprisingly, after standing for four hours at room temperature, we found that the...
Annals of clinical and laboratory science, 2021
Journal of clinical laboratory analysis, 2016
The goal of this work was to determine whether there are clinically significant fluctuations in t... more The goal of this work was to determine whether there are clinically significant fluctuations in the level of serum creatinine on serial determinations, especially in the borderline range (1.1-1.3 mg/dl), after specimen storage. Sixty-one serum samples were analyzed. They were divided into three categories based on the initial serum creatinine measurement: low (≤1.0 mg/dl), borderline (1.1-1.3 mg/dl), and high (≥1.4 mg/dl). The specimens were stored at 4°C and run on the Siemens Advia 1800 chemistry analyzer on days 1, 3, and 11. Statistical comparisons of the three groups were made using the unpaired t-test, yielding a two-tailed P-value for each group comparison. The P-values ranged from 0.0829 to 0.3892, indicating no statistically significant difference between the standard deviations of each group. Mild-to-moderate fluctuations in precision occur in successive serum creatinine determinations. The overwhelming majority of these fluctuations should not affect clinical decision mak...
Journal of clinical laboratory analysis, Jan 13, 2015
The goal of this work was to determine if immediate versus postponed centrifugation of samples af... more The goal of this work was to determine if immediate versus postponed centrifugation of samples affects the levels of serum potassium. Twenty participants donated normal venous blood that was collected in four serum separator tubes per donor, each of which was analyzed at 0, 1, 2, or 4 hr on the Siemens Advia 1800 autoanalyzer. Coefficients of variation (CVs) for potassium levels ranged from 0% to 7.6% with a mean of 3 ± 2%. ANOVA testing of the means for all 20 samples showed a P-value of 0.72 (>0.05) indicating that there was no statistically significant difference between the means of the samples at the four time points. Sixteen samples were found to have CVs that were ≤5%. Two samples showed increases of potassium from the reference range to levels higher than the upper reference limit, one of which had a 4-hr value that was within the reference or normal range (3.5-5 mEq/l). Overall, most samples were found to have reproducible levels of serum potassium. Serum potassium level...
Annals of clinical and laboratory science, 2013
Because of the metabolism of serum glucose in collection tubes containing blood samples, serum gl... more Because of the metabolism of serum glucose in collection tubes containing blood samples, serum glucose levels may be found to decrease over time. Several types of collection tubes have been designed to, at least partially, block glucose metabolism by red blood cells in blood collection tubes that may not be analyzed immediately after blood collection. These include red-top collection tubes with serum separator, grey-top tubes with a fluoride glycolysis inhibitor, and heparin-containing green-top tubes which prevent clot formation. As part of a quality assurance project, we investigated whether glucose levels differed in the three tube types from each of 18 volunteers on a prolonged standing of 4 hours. We then determined the glucose concentrations of all three tubes from each of the 18 volunteers. We used refrigerated samples over a five-day period to determine if the initial values were reproducible. Surprisingly, after standing for four hours at room temperature, we found that the...