Stability of Plasma Protein Composition in Dried Blood Spot during Storage

Round 1

Reviewer 1 Report

This approach for short term storage of plasma proteins appears to be relatively simple and for some laboratories could provide an easy and inexpensive method for holding or storage of samples. 

A few comments:

1. I could not find a reference for the procedures used in Protocol 1 or 2. Were these developed in house or were they selected from literature.  This should be clarified.
2. The comment “We have shown, using the example of tryptic components of proteins, that the composition of biosamples remains stable at -20 and + 4°C for up to 35days of storage, and at +25°C for 14 days.” Is not exactly accurate. With Protocol both at -20 and -4 there were some rare but significant degradations.
3. This is an interesting study, and the author should be congratulated. But it is a small study, which shows generally predictable results but with some problems with some samples of high concentration at 35 days.  The problem is that when samples are put down, the laboratory investigator can not say with certainty that the result was that same as on Day 1.   The author is encouraged to (a) make comment on these occasional deviations and (b) to extend the study to determine the higher preceision the probability and risk of degradation occurring beyond 14 days. 
4. I leave the decision about delaying the publication of the manuscript for additional samples being tested up to the author and the editors.

As an assist to reviewers, sending graphs in a format that requires special additional apps to open, is not helpful.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The paper concerns, dried blood spot (DBS) technology. The authors used the above method to investigated the safety of proteins on a membrane carrier by tryptic components. The authors considered the influence of time and temperatures in the aim to establish samples' stability.
In the opinion of the reviewer, the subject of this paper is interesting and current. The study belongs to subjects explored by the authors constantly, that is why appears to be worthful. However,at present form can not be accepted for publication, I suggest the following improvements before resubmission:
1. Please don't use abbreviations in the title.
2. Please correct abstract (shorten information about the method, add more about obtained results).
3. Please present the mass spectrum obtained beside Fig.2.
4. It is not clear to which substances these MS signals belong. Please identify them.
5. The fiberglass strips should be described more precisely. In this paper, the material of sorbent is important because ensured proper conditions for the storage of blood drops.

6. The most important however is the comparison of results with the reference method or experiments performed using the fresh blood sample.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I can recommend this version for publication.