Is there a minimum recovery rate that should be used for a cutoff for the applicability of the method?

Answer Explanations

• Yes (please explain and provide percent value)

  Expert 9
  I would recommend that data be gathered as part of large-scale interlaboratory comparisons that would permit assessment of the acceptable range of recoveries for different matrices and different spike levels. The latter is important as measurements are likely more variable at low MNP levels. In the absence of such empirical data, I would tentatively suggest a minimum recovery of 60% is acceptable.
• Yes (please explain and provide percent value)

  Expert 3
  According to two studies, this should be higher than 50% and 70% is deemed acceptable. 
  https://pubs.acs.org/doi/10.1021/acs.est.8b01611
  https://link.springer.com/article/10.1007/s00216-022-04447-z
• Yes (please explain and provide percent value)

  Expert 2
  Yes, there is a minimum recovery rate that should be used but it depends on the context and also on the existing standard rules and regulations. A recovery below 75% is often considered too low unless there is strong justification. In the case of a particularly challenging sample matrix or inherent analyte instability, it has been reported that the method may still be acceptable if it demonstrates good precision and accuracy despite the low recovery. A recovery in the range of 70% to 120% is commonly reported to be accepted in numerous many analytical fields like environmental and pharmaceutical. In the case of more complex matrices or when dealing with very low concentrations, a broader range between 60% to 130% may be considered acceptable. However, for methods used in quality control or regulatory compliance, recoveries above 80% are generally preferred to ensure reliability and consistency. Regulatory guidelines are connected to the applications and  the agency that issued them. For example,  the FDA, does not require 100% recovery in the case of  bioanalytical methods but  makes sure to highlight the importance of consistency, precision, and reproducibility. Furthermore, EPA typically requires a recovery  fraction between the 70–130% range, although this can vary on the specific method,  analyte and intendent application. In the same time,  the ICH Q2(R1) does not impose strict recovery minimum and maximum values but strongly encourages that that recovery should fall within acceptable limits appropriate to the method’s intended purpose.
• Yes (please explain and provide percent value)

  Expert 4
  I think that this is needed indeed, but am reluctant to provide a minimum number. 60% has been mentioned as a minimum, but I am inclined to consider recovery rates of 80 % as an indication of analytical reliability. It should also be taken into account that we do not have sufficient experience to grasp what is the actual meaning of a recovery rate of 60 or 80 % for the specific case of MNP and how stable such a number is for a specific matrix. This in the sense of the ease and effort required for the laboratory to maintain the minimum recovery.
• Yes (please explain and provide percent value)

  Expert 5
  Ideally 80% ± 35%
  Practically, anything outside of 70% ± 50% cannot be relied upon and needs to be improved.
• Yes (please explain and provide percent value)

  Expert 6
  Traditional, for common quantitative method, recovery rate (accuracy) is expected to be around 80-120%. Outside this method, it is not considered as a good method and refinement of method is needed. However, for biology samples, the variation is often higher than wet and controlled chemistry. Thus, I personally think 50-200% should be accepted in early stage of study. It means the results could be half or double, as it is discussed in study and acceptable for following implication.      
• Yes (please explain and provide percent value)

  Expert 8
  Oh goodness, it's bold to call out a specific number.  I see 50% is stated in the paper. I dont disagree with that, but I dont think the paper should say that that's a "good" criterion.
• Yes (please explain and provide percent value)

  Expert 7
  50%
• Yes (please explain and provide percent value)

  Expert 1
  Yes, normally regulatory methods prescribe the need to report limits/bounds for acceptable recoveries.  For many organic contaminants, a recovery of 70%-130% is suggested.  It varies from chemical to chemical and method to method.  But establishing such limits, help harmonize data quality and  increase rigor in the lab to produce high quality data.