Erroneous potassium results: preanalytical causes, detection, and corrective actions

Schlüter, Kathrin; Cadamuro, Janne

doi:10.1080/10408363.2023.2195936

Cited by 7 publications

(3 citation statements)

References 140 publications

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“…7 Contamination by EDTA-K anticoagulant as a cause of pseudohyperkalaemia accounted for 6.3% of the potassium rejections in this study and is common in clinical chemistry laboratories. 31 As reported in studies from Thailand in 2019 32 and India in 2020, 33 EDTA-K contamination may potentially lead to patient mismanagement. Thus, technique and order of draw need to be cautiously considered during sample collection to avoid contamination.…”

Section: Discussionmentioning

confidence: 98%

Impact of potassium test sample rejections on routine laboratory service, South Africa

McAlpine,

Chale-Matsau

2023

African Journal of Laboratory Medicine

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Background: Accurate potassium measurements are necessary for effective clinical management of hyperkalaemia. Pre-analytical factors may affect laboratory measurements, leading to erroneous results and inappropriate patient management and negatively impact the efficiency and finances of laboratories and hospitals.Objective: This study evaluated the impact of rejected potassium test requests on laboratory service.Methods: We conducted a retrospective descriptive study to assess potassium test data at a public laboratory in Pretoria, Gauteng, South Africa, using samples collected from an academic hospital, peripheral hospitals, and outpatient clinics between January 2018 to December 2018. We assessed the relationship between reasons for rejection and health facility type, as well as financial implications for the laboratory.Results: The potassium result rejection rate was 15.1% (29 806 samples), out of the 197 405 requests received. The most common reasons for rejection were old sample ( 1 day old) (41.4%; 12 348 rejections) and haemolysis (38.2%; 11 398 rejections). The most frequent reason for rejections at the central, academic hospital was haemolysis (42.0%), while old sample was the most common reason for rejection at peripheral hospitals (43.4%; 4119/9493 requests) and outpatient health facilities (57.2%; 7208/12 605 requests) (p = 0.022). The total cost of potassium sample rejection over the study period was substantial, given the resource constraints in this setting.Conclusion: Peripheral hospitals and outpatient departments accounted for the majority of rejected potassium testing results, possibly resulting from delays in transportation; causing substantial financial impact on the laboratory. Improved sample collection, handling, and expedited transportation are recommended.What this study adds: This study highlights the importance of appropriate sample collection and handling and the undesirable consequences of non-adherence to these pre-analytical considerations.

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Section: Discussionmentioning

confidence: 98%

Impact of potassium test sample rejections on routine laboratory service, South Africa

McAlpine,

Chale-Matsau

2023

African Journal of Laboratory Medicine

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“…The most common cause of potassium leakage from blood cells is hemolysis. It may result from inappropriate collection needles, intravenous catheter blood collection, syringe draw, traumatic draw, extended tourniquet time, vigorous mixing of tubes, agitation during transport and underfilling ( 3 ). Automated analyzers measure the hemolysis index in all serum/plasma laboratory samples.…”

Section: Introductionmentioning

confidence: 99%

“…Falsely elevated blood potassium may also be caused by pumping with the fist, low-temperature whole blood storage, long storage times, hereditary pseudohyperkalemia, thrombocytosis, leukocytosis, etc. ( 3 ). It is a challenge for laboratories to detect falsely elevated potassium results if it is not caused by hemolysis.…”

Section: Introductionmentioning

confidence: 99%

Pseudonormokalemia case report - What does it mean to have normal blood potassium?

Stejskal,

Šálek

2024

Biochem. med. (Online)

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Graphical abstract Highlights • Pseudonormokalemia may mean thrombocytosis, serum potassium concentration within reference ranges, and low plasma potassium concentration • The best way to eliminate both pseudohyperkalemia and pseudonormokalemia phenomenon is to completely change towards heparin-plasma as the standard material • Interpretative comments in patients with thrombocytosis over 500x109/L recommending plasma potassium measurement are helpful This case report describes a case of pseudonormokalemia, true hypokalemia. Often, only laboratory values outside the normal range gain attention and false normal results are at risk of not being noticed. However, a disease state may be masked by another pathological process. Here, a 50-year old male was admitted to the Department of Internal Medicine due to sepsis from a dental infection. Initially, serum potassium measurement revealed a normal value of 4 mmol/L (reference interval 3.8-5.1 mmol/L). Thrombocyte number was above 500x109/L. Due to our policy to recommend a repeated measurement of potassium in whole blood or heparin plasma if a patient has thrombocytosis, pseudonormokalemia was identified because the heparin plasma potassium value was only 2.9 mmol/L (reference interval 3.5-4.8 mmol/L). The physiological difference between serum and plasma concentration is no more than 0.3 mmol/L. In this case, potassium concentration were falsely elevated in the serum sample, probably caused by the high number of platelets releasing potassium during clotting. Interpretative comments in patients with thrombocytosis over 500x109/L recommending plasma potassium measurement are helpful. The best way to eliminate pseudohyperkalemia and pseudonormokalemia phenomena caused by thrombocytosis is to completely change towards heparin plasma as the standard material.

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Serum Lipid Profile and Electrolytes Reference Intervals for Apparently Healthy Children and Adolescents in Addis Ababa, Ethiopia

Mohammed,

Kassaw,

Befekadu

et al. 2024

Clinical Laboratory Analysis

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BackgroundAccurate reference intervals generated from an apparently healthy population and stratified by crucial variables such as age and gender are required to guarantee appropriate interpretation of test results. Since there were no local reference intervals in the study area, the present study aimed to establish reference intervals on serum lipid profiles and electrolytes for children and adolescents in Addis Ababa.MethodsThis community‐based cross‐sectional study was conducted from April to October 2019. Laboratory analysis was performed using the automatic biochemical analyzer Cobas 6000 (c501) from Roche. According to Clinical and Laboratory Standards Institute (CLSI) guidelines, reference intervals for lipid profile and electrolyte tests for apparently healthy children and adolescents were established. We used a non‐parametric method to calculate the 2.5th and 97.5th percentiles with a 90% confidence interval.ResultsIn children, the reference intervals for serum potassium, sodium, chloride, calcium, magnesium, and phosphate in mmol/L were 4.37–5.20, 137–145.50, 101.90–107.90, 2.34–2.70, 0.74–0.97, and 1.42–1.85, respectively; and for total cholesterol, triglycerides, low‐density lipoprotein, and high‐density lipoprotein, the respective values were 100.76–171.70, 44.16–126.36, 60.60–105.60, and 31.60–53.70 in mg/dL, for both genders. For adolescents, the reference intervals were 4.03–5.58, 137–146, 98.90–120.90, 2.39–2.70, 0.73–0.96, and 0.96–1.80 for serum potassium, sodium, chloride, calcium, magnesium, and phosphate in mmol/L, respectively; and 97.20–189.10, 40.50–143.60, 41.70–120.90, and 21.30–57.0 in mg/dL for total cholesterol, triglycerides, low‐density lipoprotein, and high‐density lipoprotein, respectively, for both genders.ConclusionThe established reference intervals in the current study revealed that both the lower and upper limits contradicted the manufacturer values as well as the available literature. The study also discovered significant gender differences in reference values for TC, TG, LDL‐C, potassium, phosphate, and chloride in the adolescent age groups.

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Erroneous potassium results: preanalytical causes, detection, and corrective actions

Cited by 7 publications

References 140 publications

Impact of potassium test sample rejections on routine laboratory service, South Africa

Impact of potassium test sample rejections on routine laboratory service, South Africa

Pseudonormokalemia case report - What does it mean to have normal blood potassium?

Serum Lipid Profile and Electrolytes Reference Intervals for Apparently Healthy Children and Adolescents in Addis Ababa, Ethiopia

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