Welcome to NP Certification Q&A presented by Fitzgerald Health Education Associates. This podcast is for NP students studying to pass their NP certification exam. Getting to the correct test answers means breaking down the exam questions themselves. Leading NP expert Dr. Margaret Fitzgerald shares her knowledge and experience to help you dissect the anatomy of a test question so you can better understand how to arrive at the correct test answer. So, if you're ready, let's jump right in.
A 67-year-old man was recently diagnosed with hypertension, dyslipidemia, and type 2 diabetes. As part of his medication treatment plan, he agrees to statin therapy. The NP appreciates that which of the following laboratory tests should be conducted about 4 to 12 weeks after starting therapy?
Would it be:
The correct answer here is C, lipid profile.
Where should you start? First, assess what kind of a question this is. Given that we're being told he was recently diagnosed with dyslipidemia as well as two other common chronic diseases, hypertension and type 2 diabetes. And we're being asked to follow-up on response to treatment. This is an evaluation question.
Let's take a look at some background information. As a drug class, statin clinical effect is predominantly through LDL reduction. The reasonable cost of this drug class, where nearly all the statins are available for about $4 a month, coupled with the decades of evidence on improved cardiovascular, cerebrovascular, and other outcomes with their use, statins are considered to be the first-line agents for dyslipidemia management.
High-intensity statin therapy will lower LDL cholesterol by 50% or more. So, in other words, if the LDL was 150, it's going to bring it down to 75 or less, whereas moderate-intensity statin therapy will lower LDL by about one-third or more.
And an example of that would be, one more time, we start off with an LDL of 150, it's going to bring it down to 100 or less. That this drug class, meaning the statins, has an excellent safety profile with extraordinarily rare reports of serious complications with statin use, even in people who have significant co-morbidity.
There is an adage helpful to remember: never order a test that doesn't contribute to the patient's diagnosis and or treatment plan. With that in mind, let's take a look at the question and the options for response.
A 67-year-old man who was recently diagnosed with hypertension, dyslipidemia, and type 2 diabetes. As part of his medication treatment plan, he agrees to statin therapy. The NP appreciates which of the following laboratory tests should be conducted about 4 to 12 weeks after starting the statin therapy?
And given that we're not being told that this patient is developing or has developed issues with statin therapy, this scenario is simply for routine monitoring. So let's take a look at the options.
Option A: AST and ALT. This is incorrect. There is an advisory to check hepatic enzymes such as AST and ALT at the initiation of statin therapy to establish a baseline, and then perhaps if elevated to trigger an evaluation for nonalcoholic fatty liver disease or other conditions that are quite common, particularly in people with type 2 diabetes. However, EBP guidelines are clear: No further routine hepatic monitoring is required beyond this baseline. The rare occasion of elevated hepatic enzymes, including AST and ALT that occur with statin therapy occur largely idiosyncratically, i.e. you can't point your finger at what's causing it, and are not prevented by routine monitoring in a person who is asymptomatic.
You might have seen out in practice, preceptors or other providers routinely measure AST and ALT in people on statins. That was a standard of care at one time. It has been a number of years since that has been discarded. So, you always have to remember the boards are up to date with practice.
Option B: CK and potassium. CK, creatine kinase, and potassium.
Well, where were they? That's also not correct. Creatine kinase is found in abundance within skeletal muscle cells, and CK and potassium could be obtained if there was a concern about statin-induced myositis. It is an extraordinarily rare condition. This question is a set up for routine follow up, i.e. something that you would discuss with the patient prior to the end of the office visit. In other words, saying to the patient, not in so many words, I'm not really concerned about you going on a statin, but we need to see the results of your statin therapy. Therefore, I'm going to send you out the door with a lab slip. We'll follow up on telehealth, whatever it would be.
So, A's not right. We're not looking for elevation of AST and ALT because the statins hardly ever cause hepatic damage. B is not right because the statins hardly ever cause an elevation in CK and potassium or muscle damage. And by the way, there is a lot of potassium within skeletal muscle cells. And that's one reason why on the rare occasion that you were thinking myositis from any kind of a situation, the CK and the potassium were checked.
Option C lipid profile, this is the correct answer. The purpose of this test is to see if LDL reduction goals were met. Doing the task prior to four weeks from the initiation of statin therapy, the clinician and the patients don't get to see the full benefits of treatment. To perform beyond 12 weeks after the statin was initiated is possibly miss the opportunity to properly monitor therapy and adjust treatment as needed, i.e. the LDL did not come down by as much as would be anticipated. Maybe the LDL, the statin dose needs to go up if that's possible, or a second med, like Zetia, is added on. So, C is the correct answer, lipid profile.
But we do need to take a look at D: CBC with WBC differential and platelet count. There are literally a handful of medications that are commonly used where periodic lab testing of CBC with WBC diff and platelet count are advised. These are typically some older antiepileptic drugs, select meds for the treatment of autoimmune diseases, and of course cancer chemotherapeutic agents. And the vast majority of you are going to be sitting for the family or the adult-gero primary care exams. There is not an expectation on that exam that you are doing the laboratory monitoring of a person receiving cancer chemotherapeutics.
When you see that rare med where there is that advisory about checking the CBC with WBC and platelet count, that is a med that has the potential to cause some bone marrow suppression. So therefore, pancytopenia, pan-all, cyto- cells, penia- low. The red blood cells would be low, the white blood cells would be low, the platelets would be low.
Key takeaway: Knowing when and why NOT to order select lab diagnostics is as important to know when to order and what to order. There is an adage helpful to remember, say it one more time: Never order a test that doesn't contribute to the patient's diagnosis and or treatment plan. That also will be helpful in your daily practice, but will be how the boards unfold.
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