Venepuncture for calcium assays: should we still avoid the tourniquet?

McMullan, A. D.; Burns, Janet E.; Paterson, C. R.

doi:10.1136/pgmj.66.777.547

Cited by 17 publications

(8 citation statements)

References 6 publications

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“…Accordingly, McMullan et al provided evidence that total calcium and albumin in serum increased modestly on application of a standard tourniquet (6). However, the authors concluded that the changes were negligible within 1 min of tourniquet placement, and therefore there was no need to perform venepuncture for calcium and albumin assays without a tourniquet.…”

Section: Figurementioning

confidence: 93%

“…We previously demonstrated that non-compliance with a rigorous preanalytical protocol for blood collection has a strong influence on laboratory testing, and might finally generate misleading clinical information for diagnosis or treatment of patients. There is inconclusive evidence that venous stasis, as commonly generated by tourniquet placement, might influence laboratory testing (2)(3)(4)(5)(6). Ideally, the tourniquet should be applied if necessary and quickly removed when the needle is safely in the vein.…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Influence of short-term venous stasis on clinical chemistry testing

Lippi¹,

Salvagno²,

Montagnana³

et al. 2005

Clinical Chemistry and Laboratory Medicine (CCLM)

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Control and standardization of preanalytical variability is a critical factor for achieving accuracy and precision in laboratory testing. Although venous stasis from tourniquet placement during venepuncture should be minimized, as it has been claimed to account for spurious and significant variations for several analytes in plasma, there is controversy surrounding its real impact on laboratory testing. The aim of the present study was the investigation of the influence of short-term venous stasis on routine biochemical testing, by measuring the plasma concentration of 12 common analytes, including proteins, protein-bound substances, enzymes and electrolytes, in plasma specimens collected either without venous stasis or following the application of standardized external pressure of 60 mm Hg using a sphygmomanometer for 1 and 3 min. Although the overall correlation between measures was acceptable, the pattern of change was mostly dependent on the length of stasis, size and protein-binding characteristics of the analytes, achieving clinical significance for albumin, calcium and potassium after 1-min stasis, and alanine aminotransferase, albumin, calcium, chloride, total cholesterol, glucose and potassium after 3-min stasis. Statistically significant differences could be observed in seven (alanine aminotransferase, albumin, calcium, total cholesterol, creatine kinase, iron and potassium) and ten (alanine aminotransferase, albumin, calcium, chloride, total cholesterol, creatine kinase, creatinine, glucose, iron and potassium) out of the 12 analytes tested, after 1- and 3-min venous stasis, respectively. The most clinically significant changes from standard venepuncture, when compared to the current analytical quality specifications for desirable bias, occurred for potassium (1-min stasis, -2.8%; 3-min stasis, -4.8%, both p<0.001), calcium (1-min stasis, +1.6%, p<0.05; 3-min stasis, +3.6%, p<0.001) and albumin (1-min stasis, +3.5%; 3-min stasis, +8.6%, both p<0.001). As most of these effects are dependent on the stasis time during venepuncture and biochemical or physiological characteristics of the analyte, these variations could likely be anticipated, allowing the most appropriate preventive measures to be adopted.

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Section: Figurementioning

confidence: 93%

Section: Introductionmentioning

confidence: 97%

Influence of short-term venous stasis on clinical chemistry testing

Lippi¹,

Salvagno²,

Montagnana³

et al. 2005

Clinical Chemistry and Laboratory Medicine (CCLM)

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“…McMullan et al fanden ebenfalls eine Zunahme von Albumin, Gesamtprotein und Calcium mit der Stauungszeit [11] ; diese wurde jedoch als moderat beschrieben und bezogen auf die Stauungszeit als vernachl ä ssigbar angesehen. Dem muss aufgrund der hier erhaltenen Ergebnisse teilweise widersprochen werden: Physiologisch relevante Anstiege fanden wir vor allem f ü r Totalprotein und Albumin, in geringerem Ma ß e auch f ü r Calcium und Cholesterin.…”

Section: Diskussionunclassified

Beurteilung des Einflusses verlängerter Stauzeiten auf nicht-normalisierte versus normalisierte klinisch-chemische Messgrößen

Lichtinghagen

Senkpiel-Jörns

Brand

et al. 2013

Laboratoriumsmedizin

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ZusammenfassungZur Darstellung des Einflusses der Stauzeit auf klinisch-chemische Messgrößen wurden bisher die mittleren prozentualen Messwertabweichungen zwischen verschiedenen Stauzeitpunkten dargestellt. Diesen Unterschieden fehlt jedoch die physiologische Relevanz, da die Ergebnisse vor allem von der Wertelage des Nullpunkts abhängen. Für eine bessere Beurteilung der Einflussgröße Stauzeit sollte die biologische Variabilität der einzelnen Messgrößen berücksichtigt werden.Bei freiwilligen Probanden (n=92) wurden klinisch-chemische Messgrößen nach bis zu 6 min Stauzeit bestimmt. Um die biologische Variabilität einzubeziehen, wurden alle Messwerte mittels z-Transformation auf die lokalen Referenzbereichsgrenzen normalisiert.Alle Messgrößen bis auf Kreatinin und Natrium veränderten sich unter der Stauung – unabhängig von der Darstellungsart – statistisch signifikant. Bei Proteinen und proteinassoziierten Messgrößen wie Calcium ergaben sich Konzentrations- bzw. Aktivitätszunahmen, während die Werte für lösliche niedermolekulare Substanzen wie Kalium und Glucose abnahmen. Die größte prozentuale Positivabweichung zeigte sich für Bilirubin (+9%), eine überraschend geringe für Calcium (+2%). Nach Normalisierung der Daten veränderte sich die Größenordnung und damit auch die Rangfolge stauungsbedingter Veränderungen: Die größte Zunahme wies das Gesamtprotein auf (+1,4 Standardabweichungen), während Bilirubin einen vergleichsweise geringen Anstieg zeigte. Für Calcium ergaben sich größere Veränderungen, die nun denen von Albumin entsprachen.Normalisierte Abweichungen spiegeln die Verhältnisse entsprechend der Physiologie besser wieder.

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“…Prolonged venous stasis for a tourniquet is cited as a reason for increased calcium3 producing changes of 0.12–0.25 mmol/l or +1.6 to +3.6% between 1 and 3 min after application,11 although some authors believe the change to be of minimal significance in practical circumstances,12 and the advice that blood should be taken without prolonged tourniquet use would seem reasonable…”

Section: Hypercalcaemia and Hypocalcaemia (Wsas And Wdf)mentioning

confidence: 99%

Best practice in primary care pathology: review 11

et al. 2007

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This eleventh best practice review examines two series of common primary care questions in laboratory medicine: (i) thyroid testing, and (ii) hypercalcaemia and hypocalcaemia. The review is presented in the same question–answer format as in the previous reviews. These questions and answers deal with common situations in men and non-pregnant women. The recommendations represent a précis of guidance found using a standardised literature search of national and international guidance notes, consensus statements, health policy documents and evidence-based medicine reviews, supplemented by Medline Embase searches to identify relevant primary research documents. In the case of the thyroid series, the recommendations are drawn from the 2006 guidelines published by the Association for Clinical Biochemistry, the British Thyroid Association and the British Thyroid Foundation. They are not standards but form a guide to be set in the clinical context. Most are consensus rather than evidence based. They will be updated periodically to take account of new information.

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Venepuncture for calcium assays: should we still avoid the tourniquet?

Cited by 17 publications

References 6 publications

Influence of short-term venous stasis on clinical chemistry testing

Influence of short-term venous stasis on clinical chemistry testing

Beurteilung des Einflusses verlängerter Stauzeiten auf nicht-normalisierte versus normalisierte klinisch-chemische Messgrößen

Best practice in primary care pathology: review 11

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