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Press Start: Lead an Empowered Life as a Clinical Laboratorian

Interpretive Lab Results

Published January 23, 2010 2:54 PM by Glen McDaniel

As physicians are inundated more and more by tons of data it has become more important to help them interpret lab data. I personally think of this not as a chore but as a wonderful opportunity to demonstrate our expertise.

We already do that to some degree now. If you think about it, shouldn't a physician know the reference interval for a glucose? Then do we include it on a report? OK, so there are different methods and the doctors may practice at different sites or use different labs, but we still don't just give them a reference guide or a cover sheet. We include the reference interval next to every result we report.

Many times the result is further flagged if it is abnormal in some way (listed as high, low, positive, negative or bolded).This is not simply as a courtesy to the physician; it also helps to ensure patient safety. We don't want a physician guessing or treating a patient inappropriately based on a misinterpreting the significance of a lab result.

Should we be doing even more for ,say, for troponin: what level is indicative of ischemia and what level is "negative"? Should we decide that a repeat test is not indicated or that a delta value is not significant? Should we suggest appropriate tests based on initial testing?Should we limit some tests to one per hospital stay, autocancel duplicates and offer a canned report explaining why?

With information technology what it is these days, such interpretation is very easy to do. There is also lots of data and research to support cut-points, reference intervals and tests which are more useful than others.

Pathologists do that sort of interpretation all the time; but that is widely accepted without debate because it is physician-to-physician communication.

Reports, at least anecdotally, are  that physicians for the most part welcome interpretive reporting and base clinical decisions on the laboratory's interpretation of a result. It seems that this is one area in which clinical laboratorians could use their unique expertise to help clinicians and patients, showcase their knowledge and create goodwill and enhance their reputation at the same time.

8 comments

Jonas:

Actually there were way more than 6 HIV tests listed, but when the physician (or more often than not the unit secretary looking at the written physician's order)  pulled up "HIV" the first 6 or 7 tests listed , by name and an order number (without explanation of their proper use) were the following.

Note: The brief explanations are mine, they dont show on the order screen the ordering person sees.

1. HIV screen- preliminary screen done in duplicate for HIV antibodies. Used in ED by patient request or ED doc suspecting high risk behavior. Followup would be on outpatient basis.

2. HIV needlestick- run on blood from the  source when an employee /doctor/EMT gets stuck. It's run stat to se if immunoglobulin is needed for the stuck employee. This is free; zero $$ charge associated with the test, by the way

3. HIV NPC -HIV on women about to deliver in ED or in labor/delivery and who have no documented prenatal care. (NPC=no prenatal care),

4. HIV 1/2 screen-this reflexes to Western blot if positive

5. HIV DNA by PCR- this is usually done on babies to test for proviral DNA of HIV since babies might not have antibodies to HIV even if infected. This has a fairly high false negative rate, mind you.

6. HIV enumeration panel- for previoulsy diagnosed HIV patients ususally. It tests for viral particles as well as the CD4 cell count. Best used to determine the need to initiate HIV antiviral treatment or see if treatment is effective

7. HIV genotype- HIV 1 protease gene sequencing of reverse transcriptase; predictive of drug resistance

So you can see how the clerk could choose the wrong test (given no explanation and having little clinical knowledge); while  the physician might not even realize the wrong test was done or might misinterpret the result. For example, I learned many clinicians just assumed that HIV genotype or HIV enumeration panel gave more information when all they needed was an HIV with reflex to western blot -if positive.

The incorrect test delays treatment, drives up cost and sometimes even confounds the doctor.

Glen McDaniel January 31, 2010 5:52 PM

Why are there 6 tests for HIV and what are they? But otherwise I understand what you are saying and I think we could do more to make things less confusing for the doctors and nurses. It's just that sometimes they will argue with you even if they are wrong. I bet patients would be happy to know the lab is helping doctors make the best use of test results. After all in real life, labs are not like House and other TV shows where doctors know everything and condut their own lab tests

Jonas L. MLS(ASCP) January 31, 2010 12:44 PM
NM

I agree about the amount of data.  Not only is it overwhelming at times, it is often in confusing or contradictory formats.  Locally, I've suggested a standard order for chemistry panels and even sharing critical value and reference lists (another issue!).

Scott Warner January 31, 2010 9:03 AM

Scott:

You are right; this is not a simple issue. I am not suggesting writing reams of interpretation, or diagnosing illnesses from lab results only; or even insulting the intellligence of physicians by stating the obvious.

I used to feel much more confident about doctors's ability to select, interpret and use lab results until I started consulting and socializing with physicians who felt more comfortable confiding in me. They often tell me the sheer volume of data (not just from labs, but nursing notes, specialist physicians, radiology etc) leaves them overwhelmed. Sometimes all they see is  a sea of numbers. Then when results conflict, what do they do? When they are going down one path and they get an abnormal result of a seemingly unrelated issue, should they act on that abnormal result?

Then there are best practices and changes in technology. As laboratorians we are are more likely to keep up in detail with our own piece of the puzzle than a physician trying to remember best practices in pharmacy, CLS, radiology, making sure they check all the right boxes and complete all the right paperwork to meet Joint Commision standards, Medical staff bylaws, hospital policy, CDC guidelines and on and on.

Even ordering a lab test can be confusing. At one lab I know of there are 6 tests for HIV. Selecting the incorrect one might change what it measures (antibody or viral particles),  when it's done (stat or batched), where it's done (in house or sent out), whether it's reflexed to a confirmatory test or not, and the cost (anywhere from $8 to $420). Getting a prompt on order, or an interpretation of the result will help the physician decide what the results mean and what to do next.

Interpretive reporting is not a substitute for clinical judgement, but-done judiciously- can help an overwhelmed physician, speed diagnosis and treatment, and contribute to patient safety

Glen McDaniel January 30, 2010 11:45 AM

Glen,

Interpretive comments are a mixed bag.  I think they are fine if there are national guidelines (lipids), if the test is extremely specific (troponin), or if method-specific information is important to know (PSA).  There are, on the other hand, any number of reasons for ordering a lab test, and an interpretive comment can be seen as too narrow; even reference ranges don't fit much of the time, since they often don't account for diurnal variation, patient condition, age, collection conditions, etc.  Any interpretive information needs to be "value added" in nature.

Let's consider INR as an example.  Should an interpretive comment contain general guidelines for therapy -- likely already understood by any physician ordering the test -- or information about bias between methods to help manage patients who are managed with home tests, office testing, or testing in various labs with different ISI values?  Laboratories seem to shy away from comments that are too specific to bias associated with a method, but wouldn't that help a physician manage treatment?

I'm not suggesting we impale ourselves with comments that explain why our results are inaccurate or different from other laboratories -- just that what we think is important may not be useful to a clinician making treatment decisions.

Scott Warner January 27, 2010 7:05 AM

In other parts of the world, interpretive reporting is not nearly as radical as it is in the US. At a recent conference, I heard clinical laboratorians from Canada, the UK and Italy describe how clinicians they serve have welcomed interpretive reporting. I will post more details if I can locate them in my conference material.

In the US, other professionals, namely pharmacists, have taken to using lab results to advise physicians on proper dosing and in some  cases even ordering the  lab tests and adjusting dosages themselves.

Pharmacists use not just PT but genetic information to adjust warfarin dosage.

http://www.theheart.org/article/826363.do

"In 2007, the FDA worked with the makers of warfarin drug products to modify the product label to indicate that a patient’s genetic makeup may affect how he or she responds to the drug. Researchers know that two genes, CYP2C9 and VKORC1, which vary slightly among different individuals, can influence warfarin’s effectiveness."  Warfarin dosage is thefore individually  adjusted based on the patient's genetic makeup.

http://www.nih.gov/news/health/feb2009/nigms-18.htm

PTT and anti Xa results are used to develop and administer heparing-dosing protocols. Again, this is done largely without laboratory input.

http://www.uspharmacist.com/content/t/hematology/c/10284/

PS It's great getting a response from Kathmandu by the way!

Glen McDaniel January 24, 2010 1:48 PM

ya i agree in this topic. Interpretating laboratory data by the biochemist not only help physicians in reducing there burden but in many aspects it help better patients care. Interpretating the data by biochemists and co-relating it with clinical history by the physicians is very helpful for both physicians and patients.

Prajwal gyawali January 24, 2010 5:25 AM
Kathmandu

ya i agree in this topic. Interpretating laboratory data by the biochemist not only help physicians in reducing there burden but in many aspects it help better patients care. Interpretating the data by biochemists and co-relating it with clinical history by the physicians is very helpful for both physicians and patients.

Prajwal gyawali January 24, 2010 5:21 AM
Kathmandu

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