Discrepancies Between Sodium Concentrations Measured by the Kodak Ektachem 700 and by Dilutional and Direct Ion-Selective Electrode Analyzers

1992 ◽  
Vol 38 (12) ◽  
pp. 2419-2422 ◽  
Author(s):  
J A Stone ◽  
J R Moriguchi ◽  
D R Notto ◽  
P E Murphy ◽  
C J Dass ◽  
...  

Abstract We have identified rare (approximately 0.2% of all samples), but clinically significant, discrepancies between serum or plasma sodium concentrations measured with the Kodak Ektachem 700's direct ion-selective electrode (ISE) method and concentrations measured with two other analyzers: the Beckman Synchron CX3's dilutional ISE instrument and the Radiometer KNA2 instrument for sodium-potassium analysis by the direct ISE method. The differences do not appear to be related to any previously identified sources of discrepancy, such as variations in triglycerides, bicarbonate, total protein, albumin, or gamma-globulin, the presence of paraproteins, or interference by benzalkonium chloride from heparinized catheters. They occurred despite the use of Gen 04 reference fluid on the Ektachem. We could not identify any drug or family of drugs that the patients had taken in common and that might influence the results. Until this problem is resolved, Ektachem users should be aware of the potential for discrepancies of > 6 mmol/L in measurements of sodium concentrations.

Author(s):  
C. Langdon Fielding ◽  
K. Gary Magdesian

Abstract OBJECTIVE To evaluate changes in electrolyte concentrations and hydration status that take place in endurance horses prior to the start of a competition and determine whether these changes would be associated with elimination. ANIMALS 19 horses entered in the 2016 Tevis Cup 100-Miles (160 km) One-Day Western States Trail Ride. PROCEDURES Heparinized blood samples were collected at 5 time points: prior to transport to the ride (T0), during check-in the day before the ride (T1), 1 to 2 hours before the start of the ride (T2), at the 15-km mark (T3), and at the 55-km mark (T4). Packed cell volume and plasma sodium, potassium, chloride, urea nitrogen, glucose, bicarbonate, and total protein concentrations were determined and compared across time points and between finishers and nonfinishers. RESULTS Signif icant differences were detected among plasma sodium, potassium, and urea nitrogen concentrations measured prior to the start of the ride (ie, T0, T1, and T2). For all variables except chloride and bicarbonate concentrations, significant differences were detected between values obtained prior to the start of the ride and values obtained during the ride (ie, T3 and T4). Only bicarbonate concentration at the 15-km mark of the ride was significantly associated with finishing status. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that significant changes in plasma sodium, potassium, and urea nitrogen concentrations can occur in endurance horses during transport to a competition and when horses are stabled overnight before an event. Additionally, a lower bicarbonate concentration following a steep climb early during the ride was associated with subsequent elimination.


1974 ◽  
Vol 20 (9) ◽  
pp. 1217-1221 ◽  
Author(s):  
Jack A Lustgarten ◽  
Robert E Wenk ◽  
Charles Byrd ◽  
Barbara Hall

Abstract An automated analyzer, in which ion-selective electrodes are used to measure sodium, potassium, and chloride in serum, was assessed in a clinical setting. Day-to-day precision, evaluated by replicate analysis of serum pools, yielded the following coefficients of variation for sodium, potassium, and chloride, respectively: 0.99%, 1.39%, and 0.67%. Values for chloride in both commercial control sera and aqueous standards were linearly related to concentration over a range of at least 10-220 mmol/liter; however, results with the potassium and sodium electrodes showed slight curvilinearity over the range 0-24 and 10-220 mmol/liter, respectively. Mean recoveries for sodium, potassium, and chloride for concentrations covering the clinically important ranges were 98.3-102.3%, 95.9-100.0%, and 97.8-102.0%. The only important differences between experimental and comparison methods in sera were falsely high values obtained with the ion-selective electrode for K+ (caused by supranormal ammonia concentrations) and for Cl- (caused by administered bromide). Mean sodium and chloride values obtained with the electrode did not differ significantly from values obtained by flame-emission photometry or coulometry for duplicate patients’ specimens, but potassium values did differ slightly (P = .05).


1988 ◽  
Vol 34 (7) ◽  
pp. 1500-1502 ◽  
Author(s):  
R L Bertholf ◽  
M G Savory ◽  
K H Winborne ◽  
J C Hundley ◽  
G M Plummer ◽  
...  

Abstract We evaluated the performance of the lithium ion-selective electrode (ISE) in the Du Pont Na/K/Li analyzer. Lithium concentrations in 106 serum samples from patients being treated with lithium were measured in duplicate with the ISE and by flame photometry. The slope of the regression line for the two methods was 1.004 with a standard error of the estimate of 0.049 mmol/L (x = flame photometry, y = ISE). Lithium measurements by the ISE method in serum or aqueous standards were linear to greater than 2.0 mmol/L. Within-run CVs for low (0.31 mmol/L) and high (1.15 mmol/L) lithium controls were 5.9% and 1.7%, respectively (n = 20). Day-to-day CVs for the same controls were 9.8% and 3.3%, respectively (n = 20). There was no significant interference when the concentrations of sodium, potassium, calcium, or magnesium were varied, nor did intervening urinary lithium analyses affect the measurement of serum lithium. Results for lithium measurement in four serum-based survey materials compared well with results by isotope dilution/mass spectrometry.


1985 ◽  
Vol 31 (3) ◽  
pp. 435-438 ◽  
Author(s):  
R H Ng ◽  
M Altaffer ◽  
R Ito ◽  
B E Statland

Abstract We evaluated the Technicon RA-1000 "random-access" analyzer for the measurements of sodium, potassium, and carbon dioxide by an indirect potentiometric method (ion-selective electrode) and for chloride by a colorimetric method (mercuric thiocyanate). For various concentrations of control materials the total precision (CV) ranged from 0.9 to 1.2% for sodium, 1.1 to 1.3% for potassium, 1.0 to 1.2% for chloride, and 2.8 to 3.8% for carbon dioxide. The system demonstrated acceptable performance in linearity and carryover. Patients' results from the RA-1000 correlated well with those from the Beckman ASTRA-8. In a study on potential interferences, we found that high concentrations of salicylate and bromide significantly affected measurements of carbon dioxide and chloride, respectively. The RA-1000 requires only 30 microL of sample for all four tests and it offers a high throughout (30 specimens analyzed for the four tests in 25 min). This precise, easy-to-use, random-access analyzer requires minimal maintenance.


Author(s):  
Alan Glassman ◽  
Kristi M Gamblin ◽  
Trevor T Zachariah

Lymph contamination of peripheral blood samples is common in reptile species due to a close association of the lymphatic and vascular systems. Grossly lymph-diluted samples are generally discarded due to potential effects on hematologic and biochemical parameters.  Differences in biochemistry values from different sample sites in chelonians are often attributed to lymph contamination. Previous studies have evaluated blood-lymph mixtures but provide limited information since the proportion of lymph is unknown. Differences in biochemistry values of pure lymph compared to plasma are unknown in chelonian species. Paired plasma samples collected from the jugular vein and lymph samples collected from the dorsal lymphatic ring adjacent to the subcarapacial plexus were collected from 11 (6 females, 5 males) Krefft’s river turtles ( Emydura macquarii krefftii ) for comparison of biochemical analytes. No statistically significant differences were found between lymph and plasma samples for chloride, glucose, alanine aminotransferase, aspartate aminotransferase, creatinine kinase, urea nitrogen, and total bilirubin.  Statistically significant (P ≤ 0.05) differences were found between lymph and plasma samples for gamma-glutamyltransferase (GGT), total protein, globulin, and uric acid. Sex and sample differences were statistically significant for sodium, potassium, calcium, phosphorous, magnesium, lactate dehydrogenase (LDH), albumin, and triglycerides, while significant sex differences only were found for alkaline phosphatase, cholesterol, and iron. Severe lymph dilution (1:1 with plasma) may cause clinically significant decreases of potassium, total protein, globulin, and LDH, and increases of GGT and uric acid in both sexes, as well as clinically significant decreases of calcium and triglycerides in female Krefft’s river turtles.


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