Which abnormal labs do you need to worry about??

blood sample

Interpreting abnormal lab values is difficult for most new grads. 

Which abnormal labs do you need to worry about? (not all slightly out of range values warrant concern)

When do you refer your patient to a specialist provider?

In answering these questions, you should first ask yourself, WHY are you ordering the labs in the first place?

You should always have clear reasons for why you are ordering labs or tests because it helps guide next steps AND you are liable for the outcomes….

So you should have very clear reasons for why: 

It’s informing your decisions for what medications you prescribe and not-prescribe.

For example, you wouldn’t want to order every panel under the sun, not only because it could be very costly for the patient, but also because you are responsible for the results. 

If you order a prolactin level on a healthy 20 year old man without reason and the lab is wildly abnormal, you will need to know what to do with the results. 

Also, if this patient doesn’t have the best insurance, his insurance may not deem this test as medically necessary and force the patient to cover the costs. 

So, it’s important to have specific reasons for why you are ordering certain tests.


An example of good lab ordering practices is as follows

You are a psychiatric NP seeing a 55 year old male patient with schizophrenia and before starting medications (an antipsychotic) you want to assess his liver functioning to make sure he can tolerate the medications which are metabolized by the liver. 

You also know that antipsychotics can affect lipid levels and cause QT prolongation. 

For these specific reasons, it makes sense to order a CMP (complete metabolic panel) and maybe a baseline EKG to assess cardiac functioning and monitor for QTc prolongation. 

So here in this example, you have very clear reasons for why you are ordering labs: it is informing your decisions for what medications you prescribe and not-prescribe. 

If the patient had significant QTc prolongation as shown by the EKG results, you would choose a different medication or start at a lower dose. 

If liver functioning was low as shown by elevated AST and ALT levels, you would: 

possibly not prescribe the medication,
start with a lower dose of medication and/or
refer the patient for more testing if suspecting something like hepatitis. 


It’s important to have information before prescribing medications, and lab work is a good window into knowing how the body’s organs are functioning. 

Too many prescribers don’t order lab work because they don’t want to have to deal with the results when they’re abnormal (which is horrifying) or they don’t know how to interpret the results so they never order them. 

Let’s not fall into these very bad practices. 

There’s so much complexity involved in the physiology causing abnormal lab values. You could spend years learning this and never feel completely comfortable. 

The goal, at least initially, is understanding the basics, what they mean, and when to refer out. You got this, and with an understanding of why you’re doing what you’re doing, you’ll be in great shape. 



Want to learn more about what you need to know to enter practice feeling confident and prepared? Sign up for my NP for NPs: Unsure to Unstoppable course

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