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I have to assume, based on the information provided, that sa is the standard error (uncertainty) of the intercept and sb is the standard error (uncertainty) of the slope. I do not have enough context to respond directly regarding a suitable “low enough” value for Sa/Sb and the technical nature of this question is not in the scope of the support that can be provided. I can share some principles and best practices, however. In method development you need to determine the slope and sensitivity as well as the Limit of detection (LOD) and Limit of Quantification (LOD). The relative uncertainty near zero is usually large. This topic of linear regression needs to cover a number of topics, including an understanding of residuals (the difference between an observed y value, and the calculated y value using the fitted line equation) and regression statistics.
The objective is to set up a calibration with a good predictability of y (analyte concentration) based on instrument response through the regression equation. It is not best practice to be measuring near zero. It is advisable to start with five to seven standard concentration points, equally spaced; covering the range of interest. Include a standard blank and select the range so that the majority of test samples would fall in the centre of the calibration range because that is where the uncertainty associated with predicted concentration is the lowest. Plot and examine the residuals, do not force the intercept to zero and calculate the uncertainty (prediction interval) for test sample concentrations using the calibration equation. Depending on the purpose of the method, you need to look at the contribution of the calibration uncertainty to the overall measurement uncertainty, and determine how significant it is.
Depending on the instrument, and purpose of the method, I suggest you reach out to your supplier for some application guidelines.
There are four possible components that could be the issue, namely the meter, ion selective electrode, application (including sampled) and the technique. To troubleshoot, I suggest you contact the supplier and ensure you have the manual and handling instructions for both the meter and electrode. Then work systematically to isolate the problem
You can refer to the ASTM D1179-16(2021)e1 Standard Test Methods for Fluoride Ion in Water or EPA method SW-846 Test Method 9214: Potentiometric Determination of Fluoride in Aqueous Samples with Ion-Selective Electrode, for a method, including the principle of calibration.
See here https://www.astm.org/d1179-16r21e01.html and https://www.epa.gov/hw-sw846/sw-846-test-method-9214-potentiometric-determination-fluoride-aqueous-samples-ion
As mentioned earlier, measuring instruments can measure more than one feature. If these 3 different features you mentioned are important for product suitability, that is, product characteristics that need to be measured; It is preferred that the MSA study be performed for each measurement feature.
It should be done for its individual parts.
Yes, you are right, ISO 13485 and ISO 14971 are mandatory. As for other standards, it depends on what your medical device is.
For all medical devices are also applicable following standards:
There are also a lot of different technical standards. For example, if your medical device is sterile, then you need to have ISO standards relating to your type of sterilization. If your device requires electricity, then it has to be electromagnetic compatible.
List of all harmonized standards are published on several links as follows:
Dear All,
Trust all is well
The advisera document toolkit for ISO 27001, ISO 9001& ISO 14001 has been a great help to our organization. We have a partnership with Advisera..
The much-awaited ISO 27001:2022 is finally here. Just want to ask the following questions:-
Looking forward to hearing from you
From your scenario, I’m understanding that your customer is a solution provider that does not own the operational infrastructure.
Considering that, ISO 27001 certification is possible for this customer considering the protection of the information in the process it controls (i.e., sales marketing).
Since the IT solutions provided are outsourced, these are out of the scope (these could be handled by means of contracts/services agreements signed with such providers).
For further information, see:
Please note that ISO 27001 provides a systematic way to implement Information Security management, and its sequence is a bit different from what you proposed:
In short:
This article will provide you with further explanation about ISO 27001 implementation: