Stability of parathyroid hormone ex vivo in haemodialysis patients

Teal, T.K.; Reed, Malcolm J; Stevens, Paul E.; Lamb, Edmund J.

doi:10.1258/000456303763046175

Cited by 19 publications

(16 citation statements)

References 6 publications

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“…Plasma/serum was separated within 4 hours of venepuncture and stored at Ϫ80°C until assayed. Intact and biointact PTH are stable under these conditions (23,24).…”

Section: Methodsmentioning

confidence: 99%

Variability of Parathyroid Hormone and Other Markers of Bone Mineral Metabolism in Patients Receiving Hemodialysis

Gardham¹,

Stevens

Delaney

et al. 2010

Clinical Journal of the American Society of Nephrology

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Background and objectives: Clinical management of mineral bone disorder in patients with kidney failure is guided by biochemical targets, in particular parathyroid hormone (PTH) concentration. The biologic variation of PTH and other bone mineral markers was measured in hemodialysis patients to better define their role in management.Design, setting, participants, & measurements: Intact PTH, biointact (whole-molecule) PTH, calcium, albumin-adjusted calcium, phosphate, and alkaline phosphatase (ALP) were measured in nonfasting samples obtained twice a week (both short-dialysis interval) over a 6-week period in 22 stable hemodialysis patients. Concurrently, samples were obtained from 12 healthy volunteers. Intraindividual coefficients of variance (CV I ) were calculated and used to derive the reference change value (RCV) required to be 95% certain that a change has occurred.Results: CV I of all markers was significantly (P < 0.05) greater in patients than in healthy volunteers. For phosphate, ALP, and PTH this implies that an increased number of samples is required to estimate an individual's homeostatic set point. CV I of intact PTH was 25.6% in hemodialysis patients and 19.2% in healthy volunteers. A greater RCV should be used for patients (72%) compared with healthy volunteers (54%). Ideally 26 specimens should be measured to estimate a patient's intact PTH homeostatic set point (within ؎10%) with 95% probability. The CV I of biointact PTH was at least as high as that for intact PTH.Conclusions: The uncertainty of PTH estimation in an individual significantly undermines its value as a tool in the management of chronic kidney disease-mineral bone disorder using current management approaches.

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“…Plasma/serum was separated within 4 hours of venepuncture and stored at Ϫ80°C until assayed. Intact and biointact PTH are stable under these conditions (23,24).…”

Section: Methodsmentioning

confidence: 99%

Variability of Parathyroid Hormone and Other Markers of Bone Mineral Metabolism in Patients Receiving Hemodialysis

Gardham¹,

Stevens

Delaney

et al. 2010

Clinical Journal of the American Society of Nephrology

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“…Many studies have found that at room temperature, PTH is more stable in plasma derived from blood samples collected into EDTA-preserved tubes than in tubes containing no preservative (48,49). PTH also seems to be more stable in EDTA-preserved whole blood than plain clotted blood samples (50).…”

Section: Sample Stabilitymentioning

confidence: 99%

PTH—A Particularly Tricky Hormone

Garrett

Sardiwal

Lamb

et al. 2013

Clinical Journal of the American Society of Nephrology

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SummaryPlasma parathyroid hormone (PTH) concentrations are commonly measured in the context of CKD, as PTH concentration elevation is typical in this clinical context. Much has been inferred from this raised PTH concentration tendency, both about the state of skeletal integrity and health and also about the potential clinical outcomes for patients. However, we feel that reliance on PTH concentrations alone is a dangerous substitute for the search for, and use of, more precise and reliable biomarkers. In this article, we rehearse these arguments, bringing together patient-level and analytical considerations for the first time.

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“…PTH stability in EDTA plasma and serum was directly compared in seven studies using second generation assays [25,29,[31][32][33][34][35]. In these, PTH was more stable in EDTA plasma than in serum (Table 3).…”

Section: Stability In Separated Serum and Plasma At Room Temperaturementioning

confidence: 99%

“…With respect to analyte stability ex vivo, most studies, with both second and third generation assays, indicate PTH to be more stable in EDTA whole blood than clotted whole blood [15,16,18,25,26,29,30], and in EDTA and lithium heparin plasma than in serum at room temperature [25,[31][32][33][34][35]. Whilst direct comparisons of lithium heparin whole blood with EDTA whole blood [25], and lithium heparin plasma with EDTA plasma [25,32], suggested similar stability could be achieved in lithium heparin preserved tubes, there was limited evidence upon which to base a recommendation.…”

Section: Recommendations For Sample Handlingmentioning

confidence: 99%

Sampling and storage conditions influencing the measurement of parathyroid hormone in blood samples: a systematic review

Hanon

Sturgeon

Lamb

2013

Clinical Chemistry and Laboratory Medicine (CCLM)

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Parathyroid hormone (PTH) is relatively unstable: optimisation of pre-analytical conditions, including specimen type, sampling time and storage conditions, is essential. We have undertaken a systematic review of these pre-analytical conditions. An electronic search of the PubMed, Embase, Cochrane, Centre for Research and Dissemination and Bandolier databases was undertaken. Of 5511 papers identified, 96 underwent full text review, of which 83 were finally included. At room temperature PTH was stable in ethylenediaminetetraacetic acid (EDTA) preserved whole blood for at least 24 h and in EDTA plasma for at least 48 h after venepuncture. Losses were observed in clotted blood samples after 3 h and in serum after 2 h. At 4°C PTH was more stable in EDTA plasma (at least 72 h) than serum (at least 24 h). Central venous PTH concentrations were higher than peripheral venous concentrations. In the northern hemisphere, PTH concentrations were higher in winter than summer. PTH has a circadian rhythm characterised by a nocturnal acrophase and mid-morning nadir. Data related to frozen storage of PTH (−20°C and −80°C) were limited and contradictory. We recommend that blood samples for PTH measurement should be taken into tubes containing EDTA, ideally between 10:00 and 16:00, and plasma separated within 24 h of venepuncture. Plasma samples should be stored at 4°C and analysed within 72 h of venepuncture. Particular regard must be paid to the venepuncture site when interpreting PTH concentration. Further research is required to clarify the suitability of freezing samples prior to PTH measurement.

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Stability of parathyroid hormone ex vivo in haemodialysis patients

Abstract: Background The stability of parathyroid hormone (PTH) in blood ex vivo is a significant practical problem for laboratories and clinicians. Several studies have suggested that PTH is more stable in blood collected into a potassium edetate (EDTA) preservative.

Cited by 19 publications

References 6 publications

Variability of Parathyroid Hormone and Other Markers of Bone Mineral Metabolism in Patients Receiving Hemodialysis

Variability of Parathyroid Hormone and Other Markers of Bone Mineral Metabolism in Patients Receiving Hemodialysis

PTH—A Particularly Tricky Hormone

Sampling and storage conditions influencing the measurement of parathyroid hormone in blood samples: a systematic review

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