Algemeen Medisch Laboratorium Emiel Vloorsstraat 9 2020 Antwerpen T : +32 (0)3/30.30.800 F : +32 (0)3/30.30.880 E: info@aml-lab.be W: www.aml-lab.be 030-MED ISO 15189

Antwerpen, 8 oktober 2012

Betreft: CHROMOGRANINE A: BEWARINGSMODALITEITEN

Tijdens de ENETS Conference in Kopenhagen in maart 2012 werd het belang van afname/bewaring

van stalen voor de bepaling van Chromogranine A onderstreept.

De snelle afbraak van Chromogranine A bij niet-conforme bewaring resulteert in verlaagde

waarden met de bepaling die wij gebruiken in het laboratorium (Kryptor®-Thermo Scientific).

Deze bevindingen zijn duidelijk weergegeven in de Poster van het Departement Klinische Chemie

van het Antoni van Leeuwenhoek Ziekenhuis (zie bijlage).

De producent heeft dan ook de richtlijnen in verband met afname/bewaring aangepast:

- Enkel serum kan gebruikt worden voor de bepaling van Chromoganine A (geen plasma)

- Indien de bepaling wordt uitgevoerd binnen 24 uren na afname, kunnen stalen best

bewaard worden op kamertemperatuur. Indien niet, is een aliquotering en bewaring bij -20

°C aangewezen.

BEWARING BIJ 2-8 °C MOET VERMEDEN WORDEN !!!

- Icterische, hemolytische of sterk lipemische stalen kunnen verkeerde resultaten geven.

Alle info vindt U terug op de website van AML (www.aml-lab.be) onder Analyses

Voor meer inlichtingen kunt U steeds terecht bij de verantwoordelijken binnen het laboratorium:

Dany Straetmans dany.straetmans@aml-lab.be Tel. 03/30 30 856

Annie Vereecken annie.vereecken@aml-lab.be Tel. 03/259 03 10

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Comparison of the Automated Chromogranin A Assay usingKRYPTOR Instrumentation with the Manual IRMA Assay of CisBio

Catharina M. Korse1, Addy Baan1, Margot E. Tesselaar2

Department of 1Clinical Chemistry, 2Medical Oncology, The Netherlands Cancer Institute - Antoni van Leeuwenhoek HospitalAmsterdam, The Netherlands

9th Annual ENETS Conference Copenhagen, 7 – 9 March 2012

BackgroundChromogranin A (CgA) has become the most important tumor marker for neuroendocrine tumors (NET) during the last decade. To meet the need for high throughput and rapid measurements the fully automated Thermo Scientific BRAHMS KRYPTOR CgA assay has been developed.

AimsThe aims of this study were to evaluate the analytical performances of the KRYPTOR assay and to compare this assay with the immunoradiometric (IRMA) assay of CisBio.

MethodsThe KRYPTOR assay is a sandwich immunoassay using Time Resolved Amplified Cryptate Emission (TRACE) technology. TRACE technology is based on a non-radiativeenergy transfer between a donor (europium cryptate) and an acceptor (XL554). The assay uses two mouse monoclonal antibodies.

The CisBio assay is a solid-phase, two-site IRMA-assay.

CgA concentrations were measured in 194 healthy individuals, 175 patients with neuroendocrine tumors and 276 consecutive patients with the KRYPTOR and the CisBio assay.

Analytical performance of the KRYPTOR assay

Test characteristics Chromogranin A (KRYPTOR):

Sample volume 8 µl

Incubation time 29 min.

Measuring rangeIncl. automatic dilution 7 – 1,000,000 µg/l

Reproducibility

Linearity

Between run-CV n104 µg/l 3.0% 30501 µg/l 1.6% 31

DilutionObserved

(µg/l) RecoveryObserved

(µg/l) RecoveryObserved

(µg/l) Recoveryundiluted 1593 100% 1827 100% 1811 100%

2 1763 111% 2183 119% 2146 118%3 1751 110% 2223 122% 2345 129%5 1753 110% 2147 118% 2271 125%

10 1718 108% 2272 124% 2336 129%

Stability

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CgA=168 µg/l

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Two samples were measured daily in thirty runs to assess the interrun precision.

Three samples were diluted automatically with recovery ranging from 100% to 129%

Three samples were aliquoted, stored at -20oC, +4oC, CgA was measured daily during one week. Recovery after 7 days at -20oC was 99% to 103%; at +4oC: 22% to 57%; at room temperature: 86% to 92%.

Reference value

95% of the healthy individuals showed CgA KRYPTOR levels below 100 µg/l with the median at 25 µg/l

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Comparison

645 samples were measured with the CisBio and KRYPTOR assay

Spearman correlation coefficient: 0.93. Passing Bablok regression: Kryptor = 1.83 + 1.03 x CisBio

Sensitivity and specificity of the CgA KRYPTOR assay were compared with the CisBio assay in 197 healthy persons and 175 patients

AUC Std. ErrorCgA KRYPTOR .896 .017CgA CisBio .880 .018 P-value: 0.52

Summary The automated BRAHMS KRYPTOR CgA assay demonstrates an excellent analytical performance. The CgA KRYPTOR shows a good correlation with the CgA CisBio assay. Attention has to be paid to the storage of serum samples: Serum should never be stored at 4oC.

Conclusion This reliable assay is an important improvement in clinical practice of patients with neuroendocrine tumors.