GENERAL QUESTIONS ANSWERS SOLUTION

If you run samples for in-vitro-diagnosis, only the sample matrices listed in “Intended Use” are allowed and approved and can be used.
If you run samples for research applications, the kit might also be used for other sample matrices which are not listed in the “Intended Use” chapter (off-label use). For example, samples from different animals, tissue homogenates, cell culture or any other biological matrix. In this case, we would recommend contacting our product specialists in the lab (support@ldn.de ), who have a lot of experience in research applications. Beside this, we have also created an extensive list of publications where our kits had been used by the research community in different studies and research projects (available upon request).

The patient should ask his medical doctor who will give him guidelines for the collection of the sample.

  • Check the number of determinations on the cover sheet of the IFU (  )
  • Check how many wells are needed for standards (STD) and controls (CTR) (double determinations are recommended) in the chapter “Materials, contents of the kit”.
  • Start calculation.

Example:
The kit includes 6 STD and 2 CTR. This means, that 16 wells are needed for the calibration curve and controls.
96 wells – 16 wells = 80 wells = 40 samples in duplicates (or 80 samples in single determination)

It is recommended to run the assays in double determinations.

The antibodies, which are used, do not recognize the natural occurring analytes directly – but the modified (acylated or methylated) analyte. This additional chemical modification of the analyte as part of the sample preparation makes the assays more specific.

No, LDN ships its goods at ambient temperatures without cool packs for a maximum of 1 week. For this period, the kits and reagents are stable. Upon receipt, the kits have to be stored as stated in the IFU and on the labels (in almost all cases this is at 2–8 °C – except for the HistaSure dipstick kit FC L-3200 which has to be stored at room temperature).

Upon receipt of the goods, they should be stored according to the IFU, chapter “Storage and Stability”, which is at 2–8 °C (except of the kit FC L-3200; please refer to the IFU).

Please refer to the IFU, chapter 5 “Sample collection and Storage”.

Please refer to the IFU, chapter 4.2 “Additional materials and equipment required”.

The washing steps can be performed manually – but an automated plate washer is recommended as it guarantees more constancy in the washing procedure.

The reader must be capable to read absorbances of 96 wells microtiter plates at a wavelength of 450 nm (in some cases a reference filter of 620–650 nm would be preferable but not mandatory).

Please refer to the IFU, chapter 2.1 “Precautions, guidelines and warnings”. In general, it is not possible to mix reagents from different lots.

Please refer to the IFU, chapter 7 “Calculation of results”. In general, the usage of a non-linear regression method such as the 4-parameter curve fit is must be used.

There are different providers who offer online calculation programs for free. Please contact us at support@ldn.de  – we will be able to send you addresses of useful websites.   

Yes, that’s correct. Our assays use competitive methods for the quantification of analytes. This means, that the OD decreases with increasing concentration of the analyte. Example:

For in-vitro diagnosis, our assays have been validated with manual procedures. Automated procedures on open ELISA processors (Gemini, Evolyzer, etc.) are possible. For details, please contact support@ldn.de.

The most important question is: what is the concentration range which you expect? If the expected range falls within the measuring range of the assay, the chances are good that you can quantify your analyte. After checking this, you should start a small proof-of-principle with a dispensable control sample.

The tissue should be frozen directly without any additives in liquid N2 and then stored frozen as cool as possible (-80 °C is preferred). Thawing should be performed as quick as possible and if advised, the addition of stabilizing buffers is recommended.

Yes, the addition of the Stop solution will change the blue color to yellow.

Please refer to the IFU. There is a chapter where it is described how to proceed with sample concentrations higher than the highest standard. In most cases it is advised to dilute the sample with zero-standard (or water) and re-assay.

Please refer to the chapter “Calculation of Results” in the IFU. When required, the dilution factor is indicated. In all other cases only the additionally diluted samples must be multiplied with the corresponding dilution factor.

Yes, we participate at different institutions with different parameters:
INSTAND: Adrenaline, Noradrenaline, Dopamine, Serotonin, 5-HIAA, Metanephrine, Normetanephrine
FAPAS:  Histamine in fish
RfB: Chromogranin A

A radioimmunoassay (RIA) is an immunoassay that uses radiolabeled molecules in a stepwise formation of immune complexes. A RIA is a very sensitive in vitro assay technique used to measure concentrations of substances, usually measuring antigen concentrations (for example, hormone levels in blood) by use of antibodies.

License Requirements for RIA Customers
In compliance with German Regulations, a copy of the customer’s current radioisotope license must be on file with LDN. Orders cannot be shipped until the license is received by our Order Entry (Radiation Protection Act of June 30, 1989).
Please contact your national official authorities to apply for this license.