Quality Assurance in the Vascular Laboratory - SD

Introduction to Quality Assurance in the Vascular Laboratory

Hi, my name's Cindy Weiland.

I'm from Columbia, Maryland,
and I'll be lecturing on quality assurance in
the vascular laboratory.

Quality assurance didn't occur
or appear in the dictionary until 1982,
and as you'll see here, I've put the definition
of quality assurance in
and highlighted the very last part of the definition,
which says, ensure that standards of quality are being met.

So recently I was asked
to write a chapter
for a textbook on quality assurance in
the vascular laboratory.

And what I was amazed to find out in writing that chapter is
that I had nothing to reference to
that I could find no other texts that included
information about quality assurance that was specific
to the vascular laboratory.

So it was a challenging task,
but, it became something that I was very interested in
and I get excited to talk about.

Developing a Quality Assurance Program

Developing a quality assurance program
takes a few steps.

You wanna identify quality indicators, which means
what are the things that you're going to look at,
then you wanna identify a threshold.

So you decide what the things you're going
to look at are going to be,
and they can be anything in the laboratory.

They could be, you're looking not only at your test results,
but you could say that you wanna see how long it takes
for patients to get an appointment.

And then what you decide is what is going
to be acceptable for that.

So, for instance, if you are looking at the accuracy
of your examinations, you need
to pick the threshold which you find is acceptable, whether
that be 90% or 80%.

That's something that you're going to need to look at
and decide within your laboratory.

Often laboratories that I've worked in have used a threshold
of greater than 80% for, for their, their,
their test accuracy.

After you've got the indicators
and the thresholds, you wanna establish
how the data's gonna be collected, who's collecting it,
how often it's being collected.

Something I would encourage is
that it is an ongoing process.

Then after the data's collected,
you wanna analyze the data and come up with your results.

And once you've analyzed the data, you wanna look at it,
see if it meets your thresholds,
and if not, develop corrective action plans.

Which means that you're gonna say, okay, well,
what's the cause of us not meeting our threshold?

And then what are we going to do to assure
that we meet that threshold?

And then what the length, what's the length of time
until we're gonna reanalyze the data?

Types of Quality Indicators

As I mentioned before, quality indicators may relate
to more than just your test result may relate in the
structure of your organization, how the exams are performed,
meaning, if their, the protocol is appropriate,
if it's being followed consistently, then the outcome
of care, which is often what we focus on with,
quality indicators,
because it really is one of the most important aspects
of your vascular laboratory.

Defining Thresholds and Data Collection

So thresholds are defined as a percentage
of acceptable deficiency, as I mentioned,
and it can be defined for numerous things.

Data collection can come from records
or lab reports, surgical reports,
other imaging modalities, questionnaires.

I suggest that the lab creates some sort of data worksheets
that organize the information.

And I would keep those very accessible to the members
of the staff so that data gets entered, regularly
as opposed to waiting till the end of six months
or a year to collect the data.

Again, define the timeframe that the,
and the volume of data that's going to be collected.

If you're a smaller laboratory,
and you're only seeing a couple hundred patients a year,
you're gonna wanna, you're going
to wanna collect data from probably almost every abnormal
exam that you, you perform.

If you're a laboratory that sees 20,000 patients a year,
it may not be as ideal to collect the, the
volume of information
that would come from that many patients.

So you need to decide how much you're gonna collect in
any given timeframe.

Example of a QA Log and Analysis

This is just an example of a QA log,
and you'll see here that we have the patient identification.

And then you look at what the, the lab study
that's been performed is the date of the study,
the correlative study.

If they had a CTA, an MRA, an angiogram surgery,
when the date of that study was,
then you write down the findings from those studies
and you match by either the location of the, the disease,
the severity of the disease,
and it was the diagnostic
criteria used appropriately in the report.

Once you have that information collected,
you're gonna look at the sensitivity of the data,
which is the probability
that the test is positive when there is disease present.

Specificity relates to the probability
that a test is negative when disease is absent,
so it's a true negative.

So we've got true positive and true negatives there.

And the accuracy is just the number of correct findings,
regardless of whether the exam is positive or not positive.

Using a Correlation Matrix

Here's a correlation matrix that we can use to find out
what the overall accuracy is.

And the, the thing to remember about the matrix
that helps you understand it a little better is,
so we've got the comparative study findings across the top
and the ultrasound findings down the side of the axis.

Anything that falls on this horizontal plane here
are actual correlations.

They're the ones that correlate if something falls on above
the horizontal axis, it refers to
that the ultrasound has underestimated the disease.

If it falls below the horizontal axis,
the ultrasound has overestimated disease.

So let's take a look. Here's an example of how you would,
where you would put place the information once you
have it in the matrix.

So we have here the duplex findings for the right ICA,
the duplex findings was 70 to 99% stenosis.

And for the right a CA,
the angiography showed a 75% stenosis.

People often ask, well, if they're not, if the
angiography is reported as a given stenosis,
how do we correlate to that?

Or if the MRA
or the CTA say 81% as opposed to 80 to 99%,
if the stenosis, category falls within your range of
what the duplex ultrasound has been interpreted as, then
that is a correlation.

So as we see here, that 75% falls into the 70
to 99% stenosis rate rating.

So we look down at the carotid duplex findings,
and you find your 79 9% stenosis range.

And then what you do is you come across the axis
and you find where the 70 to 99% is for angiography.

You match those two, two up and you enter your data there.

So you would put a one there or a hash mark first
before, while you're figuring out all your data.

So again, for the left side, you see
that the left ICA was on the ultrasound, was interpreted
as normal, and then the left ICA
by correlation of angiogram was reported
as 20% stenosis.

Well, that is not a correlation, okay?

So what you're gonna do is you'll find for the ICA
for the ultrasound rather, where is your normal,
here's normal, but then you wanna come across
and put it underneath the angiogram finding,
which would fall be below the one to 49%.

So you would enter that number here.

Analysis for Non-Percentage Tests

If you're going to put information for, for,
tests
that don't have a percent stenosis, that you're just,
they're tests that are either positive
or negative, such as a venous exam,
you're gonna use what's called a high square.

It isn't as detailed as the matrix.

What it does is just basically show what's
positive and what's negative.

And if they fall on the horizontal axis,
that means they've correlated.

If they fall outside of that, they have not correlated.

So here you can see that the true positives
Are 59, which means that they were,
they were true positives,
that disease was present or not present.

And then the sensitivity
and specificity is calculated
using the total over here.

And it comes to be 89 per percent.

The positive predictive value was just nine over 15
to 67%, and the negative predictive value is 98%.

Peer Review and Ongoing Quality Assurance

Peer review can be used again for, to look at exam findings,
report content, a adherence to diagnostic criteria.

Technologist review is a good way
to do this is just another form of qa.

When you don't have correlative exams,
you could do this on any of the exams performed in your,
your laboratory.

And it should be done consistently for everyone
that's reading or performing in the laboratory.

And then the findings need to be com communicated
to the staff on an ongoing basis to assure
that they can adjust what they're doing,
or they know when they're doing things right
or when they're doing things that may not be right.

So it's really important that once you have the data,
that you use the data, again,
you should develop corrective action plans to ensure
that you correct those things
that aren't being done appropriately.

You should have regular QA meetings
and keep meeting minutes so that they're distributed to,
people are unavailable for the, the meeting at that time.

Get all the staff involved.

It's very important that everybody takes ownership
of the quality assurance program
and that everyone works towards the same
goals in the laboratory.

It's important too to have staff be accountable, for
what they're doing in the laboratory.

Often I think that it's, it's a difficult thing
to hold people accountable, but it's very important.

And if you get them involved
and get them to take ownership, it helps.

It definitely helps with the quality assurance program,
and it should, again, be an ongoing process.

You don't wanna wait for a year
to collect your quality assurance data.

You want to do it every couple of months, every few months
to assure that any problems that arise come to the attention
of the lab and that you can make any corrections needed at
that time.