Performance Characteristics of Six Intact Parathyroid Hormone Assays

Abstract

The aim of this study was to evaluate the performance characteristics of 6 intact parathyroid hormone assays: Access 2 (Beckman Coulter, Fullerton, CA), ARCHITECT i2000(SR) (Abbott Diagnostics, Abbott Park, IL), ADVIA Centaur (Siemens Healthcare Diagnostics, Deerfield, IL), Modular E170 (Roche Diagnostics, Indianapolis, IN), IMMULITE 2000 (Siemens Healthcare Diagnostics), and LIAISON (DiaSorin, Stillwater, MN). Sample collection tubes and storage conditions were compared. Imprecision studies were performed using commercial quality control materials. Linearity was assessed using pools prepared from samples. For method comparison, serum and EDTA plasma samples were tested by all methods, and the ARCHITECT was used as the comparison method. Reference intervals were determined using various vitamin D cutoffs. The types of collection tubes and storage conditions are more important for some methods than others. Total coefficients of variation were 10.9% or less. The maximum deviation from the target recovery for linearity ranged from 5.0% to 82.2%. Bland-Altman plots demonstrated percentage biases ranging from -36.3% to 24.4%. The lower limit of the reference interval was not influenced by vitamin D status, whereas the upper reference limit was affected.

The relationship between PTH and 25-hydroxy vitamin D early in pregnancy

“…25(OH)D and PTH measurements were each performed over a 3 week time span, with PTH measurements being performed 10 months after the 25(OH)D measurements using the same aliquots after a second thaw. Performance characteristics of six intact PTH assays (including Diasorin Liaison) were reported recently by ARUP Laboratories 6 . Not shown in that publication was the mean fresh serum PTH concentration in 15 healthy volunteers (6·1 pmol/l), as measured by Liaison, compared with measurements after 3 days at −70 °C (6·2 pmol/l, P = 0·025), 24 h refrigeration (6·0 pmol/l, P = 0·08) and 48 h (5·7 pmol/l, P = 0·004).…”

Point-of-care diagnostics for niche applications

“…The majority of these assays use a sandwich immunoassay with capture and detection antibodies that recognize unique epitopes of PTH. Many of these assays have been compared with one another, and they have shown some key differences (Cole et al, 2007, La'ulu and Roberts, 2010, Santini et al, 2004). The differences in reported values between assays can potentially be attributed to the different recognition elements used in the diagnostic tests.…”

Management of CKD-MBD in non-dialysis patients under regular nephrology care: a prospective multicenter study

“…Another limitation is the possible variability between the different intact PTH assays used in the different centers. Based on the study of La'ulu and Roberts [29], we can estimate total coefficients of variation between different intact PTH to be 10.9 % or less, but percentage biases may range from -36.3 to 24.4 %, based on Bland-Altman plots. However, as suggested by the same authors, we can assume that assay-specific decision limits were used in each participating center.…”