Two-site assays for calcitonin

Calcitonin concentrations were determined by a sob'd phase

two-site enzyme immunometric assay (Medgenix, Düsseldorf,

Germany). Calcitonin is captured by a monoclonal antibody

directed against it and immobilized on microtitre plates. Detection

is performed using a second monoclonal antibody labelled

with horseradish peroxidase. The assay requires incubation

of the sample overnight at 4 °C, followed by a short

incubation of 15 min after five washing steps. Serum, heparinized

plasma or EDTA plasma may be used without extraction.

The lower potential detection limit of the assay was determined

and defined as the point of the calibration curve 3 standard

deviations above B0 (based on 16 measurements of the 0-

standard). To obtain intra- and inter-assay variations, samples

with known concentrations of calcitonin (10—613 ng/1) were

repeatedly measured in eight separate assays and simultaneously

measured eight times in one assay. Samples from five

patients with medullary thyroid carcinoma and high concentrations

of basal calcitonin were serially diluted in calcitonin-free

medium (provided with the assay) to estimate linearity of the

assay in the range of measurement (2—1000 ng/1). The specificity

was tested by assaying various concentrations of calcitonin

from salmon and eel and various concentrations of different

fragments of human calcitonin.

The fragments of human calcitonin and eel calcitonin were a

gift from Dr. Kabay, Ciba Geigy, Basel, Switzerland; salmon

calcitonin was a gift from Sandoz, Nürnberg, Germany.

Additionally, basal and pentagastrin stimulated calcitonin concentrations

in 29 normals were also measured by a commercially

available immunoradiometric two-site assay of calcitonin

(ELSA-hCT, CIS, Dreieich, Germany). The assay is based on

two monoclonal antibodies (8) against calcitonin (calcitonin

sequences 11 — 17 and 24—32), uses a single incubation step

and has a detection limit of 2 ng/1.

Reference: Determination of Serum Calcitonin by Immunometric Two-Site Assays

in Normal Subjects and Patients with Medullary Thyroid Carcinoma

By Angela Zink, E. Blind and F. Raue

Eur. J. Clin. Chem. Clin. Biochem.

Vol. 30, 1992, pp. 831-835

you can use blood serum as a sample and you can also modified this assay as per ur requirement.

I need someone who can analyze samples in his lab as I have no necessary instruments