Take Heart!

Physician Office Lab

By Jim Poggi

Cardiac tests and the physician office lab

At this time of year, we are typically in the middle of respiratory testing season and running hard to keep up with demand. So, why should we focus time on heart disease screening and follow-up tests now (other than that February is right around the corner and is “heart month”)? Because heart disease is the leading cause of death in the United States, and our customers see patients for diagnosis and follow-up for heart disease every day.

So, every day our customers will be initiating or modifying a patient treatment plan for a heart patient. We can influence the path to care for a disease that is also implicated in two other serious disorders: stroke and diabetes, which are also leading causes of death in the United States. For additional perspective, 28.4 million Americans are diagnosed with heart disease annually. That’s over 11 percent of the U.S. adult population.

In 2015, there were 15.3 million physician office visits with heart disease as the primary diagnosis, and heart disease accounted for 1.9 million visits to hospital outpatient departments in 2015. There were over 1.1 million emergency room visits for heart related causes in 2015.

With that backdrop and the knowledge that lab tests influence 70 percent of all medical decisions, we can be a positive impact in providing lab tests that can help diagnose heart disease quickly and accurately, as well as providing follow-up tests to assess the patients’ response to treatment.

Screening and predictive tests
A summary of the most commonly used screening and predictive tests are below:

Test name	Indicates	Waived?	Comments
Basic/comprehensive metabolic panels	Overall metabolic status	Some	General health screen
Cholesterol/HDL/Triglycerides	Elevated lipids increase risk	Yes	Multiple options are available
Glucose	Elevated glucose increases risk	Yes	Some glucose methods are available on lipid panel instruments
Electrolytes	Metabolic imbalance can be related to heart disease	Some methods	Electrolytes can indicate heart failure or hypertension
D-dimer	Clotting risk	Some methods	More stroke related
hs-CRP	Inflammation	No	Can indicate an underlying condition that could lead to heart disease
Beta natriuretic peptide	Increases in congestive heart failure	Yes; some	Useful for initial diagnosis of heart failure and follow up
PT/INR (prothrombin time)	Clotting risk	Some methods	More stroke related

Acute markers
While a handful of primary care practices also perform either troponin I or arterial blood gas testing in the office, this practice is uncommon. Most primary care practices will perform tests that allow them to treat quickly and effectively during the office visit. As a result, when confronted with the prospect of diagnosis of an acute myocardial infarction (troponin I) or severely compromised blood gases, the typical practice will immediately direct the patient to an emergency room, where appropriate treatment is more readily available.

Opinion is divided in my experience in both urgent care centers and free-standing ER facilities on these tests. There are some that perform them, but most do not for reasons similar to primary care practices. When dealing with facilities like urgent care and free-standing ER centers, your best approach to positioning the more acute markers is to ask directly where they draw the line on acute tests. This is not only a sound way to qualify the customer, but is clearly in line with the goal of being perceived as a well-informed and well-grounded consultant.

On the horizon
With the rapid proliferation of new tests, particularly molecular based assays in microbiology, infectious disease and respiratory testing categories, what’s new and what’s on the horizon for heart disease testing?

There are a ton of lipid fractionation and lipid phenotyping tests out there. Most are performed in specialty lipid testing reference labs and not applicable in our market yet. They try to identify, quantify and risk stratify less well understood lipids. Some examples include apo A-1, apoB-100, LDL subclasses and other even more esoteric markers. From my review of the literature, I don’t expect the dust to settle over which of these tests will hit the mainstream in the POL for quite some time.

There are a few new tests and test combinations that may become pertinent to us sooner than later. All are making their appearance in the acute care market. First, while high sensitivity Troponin I is becoming available on an increasing number of chemistry system platforms we sell, it is clearly an acute care marker and unlikely to become a mainstream factor in primary care. The next is a new multi-test risk assessment tool (high sensitivity Troponin I, glucose and glomerular filtration rate). This 3-test combination is finding its way into the acute care market to stratify risk of acute coronary syndrome. Due to the number and type of tests in this panel, I doubt it will make a meaningful impact on testing in primary care. Finally, small dense LDL testing is entering the hospital and reference lab market as a newer risk stratification marker. Of all the new tests, it is my impression that this one is most likely to come into our market next. Depending on whether studies in process will demonstrate whether it is a better way to assess risk of a future heart attack, it could well become part of the routine lipid panel down the road. Keep an eye out for that test and I will let you know what I hear as well.

While molecular has rapidly advanced in several other testing areas, it is yet to become a factor in heart disease testing. I predict that as things change, it is most likely to find its way in risk prediction and preventive medicine. So far, tests in this area are still in the early research stages.

February may be heart month, but heart disease is a year-round leading cause of death, and our customers deserve our best efforts to provide them with the right test mix to diagnose and manage this serious disease. So, stop reading and get selling cardiac tests!