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CDRH Learn - Deficiency Writing for Third Party Reviewers: Examples

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Hello! Welcome to the CDRH Learn module titled Deficiency Writing for Third Party Reviewers, 

Examples. I'm Helen Jiang at the FDA's Center for Devices and Radiological Health or CDRH. 

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As we know, practice makes perfect! In any area, using examples that apply concepts often helps us 

master the principles.

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The deficiency writing program consists of two modules. First, we have the first module titled 

"Deficiency Writing for Third Party Reviewers," which goes over the theory of deficiency writing. I 

encourage you to watch that one first. This module is the second one in the series, where we'll go over 

examples and check your knowledge about writing deficiencies.

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Here are the learning objectives for this module. First, we'll review the basic principles of deficiency 

writing in four-part harmony format that we covered in Module 1. Then, we'll identify aspects of fourpart harmony in a well-written, complete example. And finally, we'll do a knowledge check where you 

get to identify missing parts in several incomplete deficiencies.

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Before going into details, I'd like to make the following disclaimers. First, the deficiencies and examples 

listed intend to illustrate teaching principles only. Second, this presentation does not intend to imply, or 

establish any regulatory policy with any device-specific examples. Finally, please review applicable FDA 

laws, regulations and guidance for cross-cutting, or specific matters.

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According to four-part harmony format, each deficiency should include the following four parts: First, a 

brief summary of what was provided in the submission; Second, what is missing or deficient; Third, why 

this information is needed; and fourth, what needs to be provided for reviewers to make the decision,

including any potential alternatives. 

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The following example and all other examples are slightly modified from the examples in the Deficiency 

guidance document presented in Module 1. I'll present the full deficiency first, and then we'll go over 

each part of the four-part harmony in the full deficiency.

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Now let's look at the full deficiency. As you can see, it's very long. To understand it fully, I'll read the full 

deficiency for you. "You have proposed that your powered muscle stimulator is intended to be used in 

the home environment by lay users. However, you have only included professional labeling intended for 

healthcare providers. The FDA recommends in our "Guidance on Medical Device Patient Labeling" that 

you provide patient labeling for your device since you intend for patients to operate the device. 

Therefore, please submit patient labeling that explains your device and includes directions for use, study 

design and results, and any additional relevant information. Please use clear language and terms 
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understandable by the lay person. Please also include a glossary of all relevant medical terms and 

ensure that all appropriate contraindications, warnings, and precautions from the professional labeling 

are conceptually the same but are rewritten for understanding by the lay person". 

Please note, the word "you" in the deficiencies presented in this video refers to the applicant or the 

sponsor.

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Now let's take a look at the deficiency, one part at a time. Let's start with Part 1: what was provided. 

"You have proposed that your powered muscle stimulator is intended to be used in the home 

environment by lay users".

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Next is Part 2 - what is deficient. "However, you have only included professional labeling intended for 

the healthcare providers".

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Part 3 identifies why it is needed, by citing corresponding guidance or standard. 

In this case, it says, "The FDA recommends, in our "Guidance on Medical Device Patient Labeling", that 

you provide patient labeling for your device, since you intend for lay persons to operate the device." Of 

note, please provide the web link right after the Guidance name, as we did not include it here for 

brevity.

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And finally, Part 4 identifies what is needed. This slide shows the part of the full deficiency that explains 

this. 

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Putting all 4 parts back together in color, here is the full complete deficiency again. Part 1, what was 

provided, is in black. Part 2, what was deficient, is in red. Part 3, why additional information is needed, 

is in purple. Part 4, what is needed, is in green.

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Now that we have seen a good example, let's do a knowledge check using other examples!

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In the following slides, I'll provide 3 example incomplete deficiencies. We'll give you, the third party 

reviewer, a chance to think about the answer and then we'll provide the answer. Please read the sample 

deficiencies first and then look for the missing part. As you do this, think about why it is important to 

add the missing part.

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Deficiency #1 reads as follows, "You did not identify fresh and frozen samples in the line data, nor did 

you stratify clinical performance by fresh and frozen status. To ensure we better understand the 

performance of your test under your proposed conditions of use identified in your draft labeling, please 

update the line data to indicate fresh and frozen status and stratify clinical performance by this 

parameter". What do you think is missing in this deficiency? When you read it, do you know what I am 
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talking about? Not really, right? Because part 1 "what was provided" is missing, so the context of this 

deficiency is not clear.

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Here we listed all 4 parts of a complete deficiency with check boxes, and the part that is missing is 

unchecked and in red. So, for Deficiency #1, the answer is part 1 is missing.

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After we add the missing Part 1, in bold and red, this became a more complete deficiency. "You provided 

line data for your prospective study for your in vitro test. From the dates listed in the line data for 

specimen collection and inoculation, it appears that both fresh and frozen samples were tested." Part 1 

is very important because it reminds the sponsor of the context and lays the foundation for the next 

three parts of the deficiency.

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Now let's look at another example, Deficiency #2. It says, "You referenced the currently FDA-recognized 

version of ISO 7886-1 in your submission for your hypodermic syringe and did not include a declaration 

of conformity. 

You should demonstrate conformance to Clauses 6 and 7, or, demonstrate substantial equivalence SE 

otherwise, because your identified predicate device was determined to be SE through conformance to 

this ISO standard. Therefore, please provide the test results from these two tests, or provide a 

declaration of conformity to the methods and acceptance criteria identified in Clauses 6 and 7 of this ISO 

standard so that FDA may assess whether your performance data support the SE of your device to the 

predicate device". What is missing in this deficiency?

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Part 2 is missing this time. So, when the sponsor reads it, they don’t know what was wrong or deficient.

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Let's see how we can improve this deficiency by adding in Part 2, what is deficient! "While you have 

submitted several tests under ISO 7886-1, you did not include a summary of your testing regarding limits 

for acidity or alkalinity or limits for extractable metals, Clauses 6 and 7." This is very important because 

it explains what the problem or our concern is, otherwise the sponsor may not know what was wrong 

and therefore may not be able to address it fully.

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Finally, let's look at a more complicated example where a third party reviewer has more than one 

concern or deficiency under one category. The deficiency says, "You have provided the protocols and 

results from a cytotoxicity test using your device in its final finished form, as recommended by the FDA 

guidance document "Use of International Standard ISO 10993-1". However, we have identified the 

following inadequacies in your testing. A. The currently FDA-recognized standard ISO 10993-12

recommends the use of surface area to determine the amount of device included in the extract. Please 

provide information to demonstrate that the use of weight to determine extraction ratio has an 

equivalent or greater amount of test article as compared to the use of surface area. "

Section B is not included here for brevity. If you cannot provide an adequate rationale, FDA 

recommends that you complete new cytotoxicity testing using a sample preparation approach 
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consistent with the surface area recommendations in the currently FDA-recognized version of ISO 

10993-12." What is missing from section A of this deficiency? 

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Part 3 is missing in this example section A, right? Basically, the third party reviewer did not explain why 

they ask for the new information or alternatively, ask for a new set of testing.

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Let's add the missing Part 3 back in red and bold for section A. That is, "We are concerned that use of 

weight, instead of surface area, may result in a false negative finding from the study. That is, a negative 

finding may occur as a result of insufficient sample being present in the test system". This is very 

important, because the third party reviewer is expected to explain, or justify, the request for certain 

information that is definitely needed for the 510k review decision, and not just what is "nice to have". It 

also provides the general guiding principle so that the applicant can apply it to other similar issues.

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Let's summarize the four key takeaways we have covered in this module. One, the FDA follows least 

burdensome principles and guidance. Two, writing clear deficiencies helps improve understanding and 

resolution of regulatory issues. Three, a well-written deficiency consists of four parts, and four, 

including all four parts allows complete understanding of the issues and expectations.

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For more information, please visit the FDA third party review program at the link below, and if you have 

any questions about this training module, please contact the mailbox at the email listed on the slide. 

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Let's conclude this module with your call to action! First, fully understand the regulatory issues, and 

details of each submission. And second, apply the principles presented in this and the companion 

module when writing deficiencies and corresponding with sponsors.

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We hope this presentation is helpful to you. Thank you for watching! 

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