Lab Interpretation Resource?

[secretwave101]

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We had a doctor make a list of common liver panel tests on a white board today. He then filled in fictional numbers for each test and asked us what the likely problem was. He started each scenario by asking us what each lab value meant in general (physio), and then what it would mean if the test was low or high.

I'm wondering if there is a resource out there that has info like this for a good number of common lab tests. I don't recall anything like that, but I'd think there's something available.

I'm hoping there's something good for free on-line, but so far I've only found www.labtestsonline.org, with is really good and not commercial, but is geared toward patients and is weak on explanations of what is being tested (eg - the hepatitis tests).

 

[DOtobe]

At LECOM we used a book called "Bakerman's ABC's of Interpretive Lab Data" that has that kind of information. It tells normal values and then what high or low levels might indicate. It has every lab test imaginable in it. It is a nice book, and it is the perfect size to fit in the pocket of your white coat.

 

[Blade28]

Originally posted by DOtobe
At LECOM we used a book called "Bakerman's ABC's of Interpretive Lab Data" that has that kind of information. It tells normal values and then what high or low levels might indicate. It has every lab test imaginable in it. It is a nice book, and it is the perfect size to fit in the pocket of your white coat.

I use that too, but the PDA version.

 

[secretwave101]

Yeah, it looks pretty great. But it's 50 bucks PDA. Anyone know of any websites that might compare? I've spent quite a bit on the textbook thing this year and I'm trying to tone it down.

 

[ckent]

Why don't you just use your internal medicine text for interpretation of lab results? Besides having normal lab ranges in them, they all have things like hyperphosphatemia, hypokalemia, liver enzyme abnormalities that are explained in them. You will need to get one eventually. The three most popular are Harrison's, Cecil's, and Current Medical Dx and Treatment. Even though it's not the most useful, I think that most med students should at least have a copy of harrisons sitting at home. Current in the most useful, but they come out with a new edition every year, so you might want to wait until your clinical years before you purchase that book.

 

[secretwave101]

Yeah, I've got Harrison's.

In reality, you probably don't need ANY book other than that, right? It's just huge and, in the case of lab interpretation, pretty cumbersome.

Just looking for a quick reference guide that gives the meaning of the test, and the DD's for high and low values.

But as you said, it's in any medical text book, so I'm NOT shelling out another 50 bucks to Skyscape for a PDA program that does this.

Also, I did find a free PDA program that is pretty limited, but does talk about some of the major lab tests. This program, plus my 50 dollars seems like it'll work.

 

[Samir Desai]

When I was a medical student, lab test interpretation was a difficult area for me. Not much has changed since then because the students I work with, like many of you, continue to struggle with lab test interpretation. In my opinion, it's an area that doesn't get the emphasis it deserves during medical school. We just don't do a good job of teaching lab test interpretation to students.

As those of you who are doing clerkships have already seen, abnormal lab tests are quite common, especially in hospitalized patients. Almost every patient who gets admitted has a battery of tests that is routinely ordered and more often than not, at least one of the tests is abnormal.

If you are working up a new patient and you find one or more abnormal lab test results, here's what I suggest that you do:

1) Look up the differential diagnosis for the abnormal lab test - a lot of students stop right here but the honors student takes it several steps further (see below)
2) Try to determine if the abnormality supports or confirms your working diagnosis (i.e., the diagnosis you think the patient has based on the history and physical).
3) If it doesn't seem to have anything to do with the working diagnosis, ask yourself if it supports one of the other diseases in the differential diagnosis of the patient's complaint. If it does, you may have to rethink your working diagnosis.
4) If it doesn't have anything to do with the patient's clinical presentation, then try to develop an approach for determining what the cause of the abnormality is. Your attending may very well ask you "what do you want to about this abnormal lab test".

Some lab tests that you order may take days to come back. For these pending lab tests, while waiting for their return, it's a good idea to read up on them so you know what to do should they come back abnormal. Too often, students wait for the results of these pending tests and then when they come back abnormal, they are not sure what to do because they didn't read about them. To avoid this situation, ask yourself what will I do if this test comes back abnormal. That way, when the test does come back abnormal, you can turn to your resident or attending and say "this is what I believe we should do". Residents and attending physicians are often pleased with this type of response because it shows them that you are problem-solving. By the way, problem-solving skills is an area on the evaluation form that attendings and residents are asked to comment on.

Just some tips on lab test interpretation - hope it helps,

Samir Desai, MD
Assistant Professor of Medicine
Baylor College of Medicine

 

[Samir Desai]

In my last post, I forgot to comment on resources that are available to tackle the challenges of lab test interpretation. Many students consider the purchase of a lab test guide to be a good investment. Some reasons for this include the following:

1) Lab tests are ordered left and right in just about every clerkship
2) They often come back abnormal
3) Traditional textbooks of medicine (like Harrison's) are not lab books. Although they do discuss lab test results, they do so as part of the discussion about a particular disease. Of course, patients don't tell you they have disease X but instead present with symptom A, sign B, or abnormal lab test C. So, you have to work backwards, which is one of the reasons lab test interpretation is so difficult.

Having said this, assess your own situtation. If you believe that Harrison's or other text is doing the job for you (see my last post on this topic), then you probably don't need anything else. If the resources you are using aren't doing the job for you, then you should consider buying a lab test guide. Most lab test guides are priced at $30-40. When deciding which one to buy, take a look at some of the books out there and see which one fits your style of learning and your needs.

Good luck,

Samir Desai
Assistant Professor of Medicine
Baylor College of Medicine

 

[secretwave101]

That was, quite possibly, the most helpful response I've seen on SDN...even though it'll probably help you sell your books.

Thanks, doc.

 

[missMD]

secretwave101
I tried a search and came up with this:
http://www.sh.lsuhsc.edu/fammed/OutpatientManual/content.html