Parathyroid hormone (parathormone, parathyrin) - PTH, intact

Catalog Number: 11972103160

INTENDED USE

Immunoassay for the in vitro quantitative determination of intact parathyroid hormone in human serum and plasma for the differential diagnosis of hypercalcemia and hypocalcemia. This assay can be used intraoperatively.

The electrochemiluminescence immunoassay “ECLIA” is intended for use on Elecsys and cobas e immunoassay analyzers.

STORAGE AND STABILITY

Stability:
unopened at 2-8 °C up to the stated expiration date
after opening at 2-8 °C 12 weeks
on the analyzers 8 weeks

Store at 2-8 °C.

Do not freeze.

Store the Elecsys reagent kit upright in order to ensure complete availability of the microparticles during automatic mixing prior to use.

CALIBRATION

Traceability: This method has been standardized against a commercial PTH test (RIA).

The recovery of the NIBSC 95/646 (WHO) standard was assessed by testing dilutions in human serum covering the measuring range (40-4000 pg/mL) on 16 analyzers (cobas e 411 and cobas e 601 analyzers).

The mean recovery was 100 % ± 4 %.

Every Elecsys reagent set has a barcoded label containing specific information for calibration of the particular reagent lot. The predefined master curve is adapted to the analyzer using the relevant CalSet.

Calibration frequency: Calibration must be performed once per reagent lot using fresh reagent (i.e. not more than 24 hours since the reagent kit was registered on the analyzer). Renewed calibration is recommended as follows:

LIMITS AND RANGES

Measuring range

1.20-5000 pg/mL or 0.127-530 pmol/L (defined by the lower detection limit and the maximum of the master curve). Values below the lower detection limit are reported as < 1.20 pg/mL (< 0.127 pmol/L). Values above the measuring range are reported as > 5000 pg/mL (> 530 pmol/L).

Lower limits of measurement

Lower detection limit of the test

Lower detection limit: 1.20 pg/mL (0.127 pmol/L)

The lower detection limit represents the lowest measurable analyte level that can be distinguished from zero. It is calculated as the value lying two standard deviations above that of the lowest standard (master calibrator, standard 1 + 2 SD, repeatability study, n = 21).

SPECIFIC PERFORMANCE DATA

Representative performance data on the analyzers are given below. Results obtained in individual laboratories may differ.

PRECISION

Precision was determined using Elecsys reagents and pooled human sera in a modified protocol (EP5-A) of the CLSI (Clinical and Laboratory Standards Institute): 6 times daily for 10 days (n = 60); repeatability on MODULAR ANALYTICS E170 analyzer, n = 21. The following results were obtained:

b) HS = human serum

Precision was determined using Elecsys reagents and controls in a separate study according to protocol

EP5-A2 of the CLSI (Clinical and Laboratory Standards Institute): 2 runs per day in duplication each for

21 days (n = 84). The following results were obtained:

c) PC = PreciControl

Elecsys 2010 and cobas e 411 analyzers
Repeatability Intermediate precision
Sample Mean SD CV SD CV
pg/mL pmol/L pg/mL pmol/L % pg/mL pmol/L %
HSb) 1 26.7 2.83 0.711 0.075 2.7 1.73 0.184 6.5
HS 2 52.5 5.56 0.853 0.091 1.6 2.07 0.220 3.9
HS 3 261 27.7 4.0 0.424 1.5 7.81 0.829 3.0

MODULAR ANALYTICS E170, cobas e 601 and cobas e 602 analyzers
Repeatability Intermediate precision
Sample Mean SD CV Mean SD CV
pg/mL pmol/L pg/mL pmol/L % pg/mL pmol/L pg/mL pmol/L %
HS 1 21.9 2.32 0.44 0.05 2.0 23.2 2.46 0.79 0.08 3.4
HS 2 35.0 3.71 0.43 0.05 1.2 80.9 8.58 2.01 0.21 2.5
HS 3 123 13.04 1.31 0.14 1.1 240 25.4 6.72 0.71 2.8

Elecsys 2010 and cobas e 411 analyzers
Repeatability Intermediate precision
Sample Mean SD CV SD CV
pg/mL pmol/L pg/mL pmol/L % pg/mL pmol/L %
PCc) Varia 0 18.7 1.98 0.276 0.029 1.5 0.535 0.057 2.9
PC Varia 1 54.6 5.79 0.657 0.070 1.2 1.11 0.118 2.0
PC Varia 2 182 19.3 2.43 0.258 1.3 3.14 0.333 1.7

MODULAR ANALYTICS E170, cobas e 601 and cobas e 602 analyzers
Repeatability Intermediate precision
Sample Mean SD CV SD CV
pg/mL pmol/L pg/mL pmol/L % pg/mL pmol/L %
PC Varia 0 18.3 1.94 0.444 0.047 2.4 0.661 0.070 3.6
PC Varia 1 54.7 5.80 0.943 0.100 1.7 0.977 0.104 1.8
PC Varia 2 184 19.5 2.65 0.281 1.4 3.11 0.330 1.7

METHOD COMPARISON

A comparison of the Elecsys PTH assay (y) with a commercial PTH test (x) using clinical samples gave the following correlations (pg/mL):

Number of samples measured: 152

The sample concentrations were between approximately 1.4 and 1880 pg/mL (0.15 and 199 pmol/L).

Passing/Bablok18 Linear regression
y = 1.01x + 4.86 y = 0.83x + 19.4
t = 0.886 r = 0.991

ANALYTICAL SPECIFICITY

No cross-reactivities were found for: Osteocalcin, PTH fragment 1-37, PTH-related protein (1-86), bone-specific alkaline phosphatase, and b-CrossLaps.