learning lab blood values?

[blindsideflank]

Are there any courses out there to learn to put the pieces together in regards to interpreting lab values?
Ill be taking this course in the summer and am excited to learn my blood gases really in depth.
http://www.tru.ca/distance/courses/hlth2573.html

I understand that patho/physiology knowledge is key to this but I feel like a course that is more specific to actual interpretation would be awesome. Do these courses exist (for nurses? anyone?) recommended books? A straight physiology book doesnt really help tie everything together.

Example, i know what lipase, amylase and WBC's are, i know what pancreatitis is but it doesnt mean I would put any of that together if someone hadnt told me such. Further, I think learning this would solidify some of my physiology, having to think things through at this level (why is there hyperlipidemia?)

 

[Carlos Danger]

If you can memorize the normal values and basic reasons for derangements in a Chem 8 or Chem 12, ABG's and CBC, you will be good to go. Then read the phys texts to understand that why.

http://www.rn.com/getpdf.php/1754.pdf

I think there's something in the "For Dummies" series on this.

 

[VFlutter]

http://www.icufaqs.org "Labs" Section.

 

[JPINFV]

People memorize normal values? ::shrugs:: It's provided on lab reports.

Now interpreting said values, including recognizing "inappropriately normal" results is a different ball game. Especially with acid base disorders.

 

[jrm818]

I don't know of any specific classes, but that doesn't mean much. That said, you can do a lot on your own.

It probably depends on exactly what specific tests you want to understand. just googling the tests will probably turn up some decent resources - honestly wikipedia is usually pretty good.

many test results are straight forward (eg increased WBC), some are more complicated (eg acid/base or anemia). Some will really be hard without a solid grounding in the basic sciences - eg its hard to understand pt vs ptt if you don't understand the coagulation cascade.

Some test require not only some knowledge about physiology, but also knowledge about how to evaluate a test and test performance/usage - eg understanding d.dimer requires you know about fibrin, clot lysis, and also sensitivity/specificity/the Bayesian approach to stats, and how properly to use a screening test.

Since the class is acid base, assuming a decent level of knowledge about renal and resp physiology (or a willingness to go back to the textbook) here's some stuff to get you started, or maybe even past the class:

http://fitsweb.uchc.edu/student/selectives/TimurGraham/Welcome.html

http://freeemergencytalks.net/2010/04/corey-slovis-kicking-the-acidosis/
with slides that almost match up: http://webapps.acep.org/sa/syllabi/tu-302.pdf

electrolyte disorders: http://freeemergencytalks.net/2010/04/corey-slovis-electrolyte-disorders-in-five-easy-steps/


and before you go too crazy diagnosing things based on your newfound knowledge of test results, remember that medicine is usually more complicated than it seems, register for smartEM (free) and listen to this enough times to understand it, and realize that tests only work when wielded by someone with solid clinical knowledge:
http://www.smartem.org/podcasts/smart-testing-back-basics

edited to add:

there are also books, eg http://www.amazon.com/Mosbys-Manual...95114550&sr=1-1&keywords=mosby's+lab+test+4th

its OK...gives you the various reasons for any given lab test to be low or high with some very basic physiology thrown in. probably many more tests than you want, but you can get an older version for cheap. I'm sure other publishers have other versions, perhaps better ones.

 

[Ewok Jerky]

I would think we could make a list of the most common/most deadly lab abnormalities.

Chemistry/Basic Metabolic Panel
Na - fluid balance, high values could be increased Na or low water, low values could be lost Na or increased water.
K - kidney function, leads to cardiac badness
CO2 - can help establish acid base disorders
Cr (creatinine) - kidney funtion, acute kidney injury, chronic kidney disease
glucose - duh
INR - risk of bleeding, risk of stroke in AFib

CBC
White Cell Count - elevations can be from infection, stress, or gluocorticoid use
H/H (hemoglobin/hematocrit) - various states of anemia
anemia can be classified by the size and color of red cells
*MCV (mean corpuscular volume - red cell size)
-increased can indicate b12/folate deficiency
-decreased can indicate iron deficiency, thalassemia
*MCH (mean corpuscular hemoglobin - red cell color)
-ok this is getting to be too much because you need to look at MCV and MCH together to classify anemia...bottom line low H/H is bad because your patient is either losing blood or not making blood, either way, they don't have enough blood.

Liver Function Tests (very basically)
AST/ALT - increased meens inflamed liver
alk phos - increased is probably a stone somehwhere in the gall bladder or billiary tree
lipase - increased meens inflamed pancreas
albumin - if its low then your liver isnt making enough protein, so its probly not making clotting factors either, and your patient is at risk of bleeding. Also, with low albumin you are losing oncotic pressure in the vascular space so you patient will be 3rd spacing fluid into their abdomen or their feet or their face.

Other Common Tests
troponin - it leaks from cardiac muscle cells when they get mad
CK - it leaks from all muscle cells when they get mad (rhabdo)
d-dimer - elevations are sensitive for PE, but not specific
sed rate - generaly indicates some inflammatory reaction
urinalysis - should be clear, if their is glucose, blood, ketones, nitrates, or bacteria, then their is something wrong in the kidney, ureter, bladder, or urethra


Here are some things you should know if you are going to be looking at lab values:
-specificity vs sensitivity
-acid base disorders and the physiology behind them (renal physiology)
-renal physiology and the mechanism of action of common HTN medications
-common physical exam findings of electrolyte and metabolic disturbances (IE: whole body swelling > liver failure and/or kidney failure)
-Common patient histories associated with electrolyte/metabolic disturbances (IE: nausea/vomiting x5 days > lots of H+, K, and water losses)

you might be suprised at how useful wikipedia is for a basic understanding
youtube has some good physical exam videos
the "made ridiculously simple" series is pretty good, especially the acid/base one
any good physiology book is a must
there is also all the endocrine stuff, but that is a lot of primary care action

**edit**
I know there is a lote more to interpreting lab results, but I wasn't about to write a textbook, I think this is a good intro for someone at the EMT/IFT level to start thining about the patient in front of them and making sense of the lab values in the chart

 

[JPINFV]

I would think we could make a list of the most common/most deadly lab abnormalities.

Chemistry/Basic Metabolic Panel
Na - fluid balance, high values could be increased Na or low water, low values could be lost Na or increased water.
K - kidney function, leads to cardiac badness
CO2 - can help establish acid base disorders
Cr (creatinine) - kidney funtion, acute kidney injury, chronic kidney disease
glucose - duh
INR - risk of bleeding, risk of stroke in AFib

1. INR is not a part of a basic or comprehensive metabolic panel.
2. BUN:Cr ratio can help determine if a patient is dehydrated.

CBC
White Cell Count - elevations can be from infection, stress, or gluocorticoid use
H/H (hemoglobin/hematocrit) - various states of anemia
anemia can be classified by the size and color of red cells
*MCV (mean corpuscular volume - red cell size)
-increased can indicate b12/folate deficiency
-decreased can indicate iron deficiency, thalassemia
*MCH (mean corpuscular hemoglobin - red cell color)
-ok this is getting to be too much because you need to look at MCV and MCH together to classify anemia...bottom line low H/H is bad because your patient is either losing blood or not making blood, either way, they don't have enough blood.

WBC count can also be increased in some types of cancers. There's a wider differential for MCV changes than that.

Liver Function Tests (very basically)
AST/ALT - increased meens inflamed liver

The big thing about AST/ALT is knowing the various ranges. Thousands? You're looking at toxic hepatitis or acute viral hepatitis. Hundreds? Fatty liver (EtOH, especially if AST predominant) or non-alcoholic. There's a couple other things that can cause increased liver enzymes, especially in regards to some drugs (metformin comes to mind immediately). Also, you won't see much with cirrhosis patients because you need liver cells to produce AST/ALT, and when the patient doesn't have AST/ALT...

Other Common Tests
troponin - it leaks from cardiac muscle cells when they get mad
CK - it leaks from all muscle cells when they get mad (rhabdo)
d-dimer - elevations are sensitive for PE, but not specific
sed rate - generaly indicates some inflammatory reaction
urinalysis - should be clear, if their is glucose, blood, ketones, nitrates, or bacteria, then their is something wrong in the kidney, ureter, bladder, or urethra

Trops: Just remember that not all elevated trops are MIs.
D-Dimers:+=active clotting someplace in the body. -=no active clotting. A positive D-Dimer is fairly useless.

 

[mycrofft]

Most reports will flag abnormals. Learn the principles so yo have an idea why they are important and how they interact, what they mean.

Maybe beyond what you will need, but learning more can only maybe cause you to go further and make more money in a safer job….

 

[Carlos Danger]

People memorize normal values? ::shrugs:: It's provided on lab reports.

Anyone should be able to hear a hemoglobin or potassium level and know whether or not it is abnormal, without looking at the report.

 

[Handsome Robb]

Anyone should be able to hear a hemoglobin or potassium level and know whether or not it is abnormal, without looking at the report.

Agreed.

I'm no ace on lab values but I am getting better at them. I do wonder how one could possibly know normal ranges of all of them but standard panels aren't that hard. Just takes work...that I'm kinda too lazy to do right now... :lol:

 

[JPINFV]

Anyone should be able to hear a hemoglobin or potassium level and know whether or not it is abnormal, without looking at the report.

Define "know." Are we talking about knowing that a 3.4 K is abnormal but 3.5 is, or are we talking about something significant, like 3 vs 4? What about the difference in normal range for hemoglobin between men, women, and children?

Now knowing that a hemoglobin of 9 is low is one thing. Knowing when it's 0.2 off is, relatively speaking, pointless because no one actually cares 99% of the time. There are a lot of abnormal lab values that are simply noted and moved past because there's no clinical importance given how minor the alteration is.

 

[mycrofft]

I would think we could make a list of the most common/most deadly lab abnormalities.

Chemistry/Basic Metabolic Panel
Na - fluid balance, high values could be increased Na or low water, low values could be lost Na or increased water.
K - kidney function, leads to cardiac badness
CO2 - can help establish acid base disorders
Cr (creatinine) - kidney funtion, acute kidney injury, chronic kidney disease
glucose - duh
INR - risk of bleeding, risk of stroke in AFib

CBC
White Cell Count - elevations can be from infection, stress, or gluocorticoid use
H/H (hemoglobin/hematocrit) - various states of anemia
anemia can be classified by the size and color of red cells
*MCV (mean corpuscular volume - red cell size)
-increased can indicate b12/folate deficiency
-decreased can indicate iron deficiency, thalassemia
*MCH (mean corpuscular hemoglobin - red cell color)
-ok this is getting to be too much because you need to look at MCV and MCH together to classify anemia...bottom line low H/H is bad because your patient is either losing blood or not making blood, either way, they don't have enough blood.

Liver Function Tests (very basically)
AST/ALT - increased meens inflamed liver
alk phos - increased is probably a stone somehwhere in the gall bladder or billiary tree
lipase - increased meens inflamed pancreas
albumin - if its low then your liver isnt making enough protein, so its probly not making clotting factors either, and your patient is at risk of bleeding. Also, with low albumin you are losing oncotic pressure in the vascular space so you patient will be 3rd spacing fluid into their abdomen or their feet or their face.

Other Common Tests
troponin - it leaks from cardiac muscle cells when they get mad
CK - it leaks from all muscle cells when they get mad (rhabdo)
d-dimer - elevations are sensitive for PE, but not specific
sed rate - generaly indicates some inflammatory reaction
urinalysis - should be clear, if their is glucose, blood, ketones, nitrates, or bacteria, then their is something wrong in the kidney, ureter, bladder, or urethra


Here are some things you should know if you are going to be looking at lab values:
-specificity vs sensitivity
-acid base disorders and the physiology behind them (renal physiology)
-renal physiology and the mechanism of action of common HTN medications
-common physical exam findings of electrolyte and metabolic disturbances (IE: whole body swelling > liver failure and/or kidney failure)
-Common patient histories associated with electrolyte/metabolic disturbances (IE: nausea/vomiting x5 days > lots of H+, K, and water losses)

you might be suprised at how useful wikipedia is for a basic understanding
youtube has some good physical exam videos
the "made ridiculously simple" series is pretty good, especially the acid/base one
any good physiology book is a must
there is also all the endocrine stuff, but that is a lot of primary care action

**edit**
I know there is a lote more to interpreting lab results, but I wasn't about to write a textbook, I think this is a good intro for someone at the EMT/IFT level to start thining about the patient in front of them and making sense of the lab values in the chart

Very detailed response! Good on you!

 

[Carlos Danger]

Define "know." Are we talking about knowing that a 3.4 K is abnormal but 3.5 is, or are we talking about something significant, like 3 vs 4? What about the difference in normal range for hemoglobin between men, women, and children?

Now knowing that a hemoglobin of 9 is low is one thing. Knowing when it's 0.2 off is, relatively speaking, pointless because no one actually cares 99% of the time. There are a lot of abnormal lab values that are simply noted and moved past because there's no clinical importance given how minor the alteration is.

So you honestly see no value in a paramedic knowing the normal range for common labs?

 

[JPINFV]

So you honestly see no value in a paramedic knowing the normal range for common labs?

No. I see value, on the other hand, in paramedics being able to interpret basic labs, which is not the same as simply knowing the ranges. It's one thing to know the ranges (which I don't think is the same as being able to interpret them), it's another thing to know that no one really cares about the K of 3.4 or the hemoglobin of 10 or the NA of 147. Granted I never had a test in medical school that asked about normal ranges. If it was off, it was obviously off, and even still normal ranges were provided 99% of the time

 

[blindsideflank]

Wow, lots of the big guns here posting. Thanks everyone. I ready the reviews on mosbys diagnostic and lab... and I think ill be picking it up.

In response to the argument (which was a misunderstanding as I think you both are actually agreeing) regarding paramedics reading lab values dont forget that there are medics from all over the world on here so what may be in scope or an expectation in one place may not be the same where you work. (I often see people arguing when it's obvious that its an American talking to a European) although I don't think was the case here.

One more question out of curiosity, does any profession other than dr/PA in your area hold the expectation of interpreting labs?

 

[Carlos Danger]

Agreed.

I'm no ace on lab values but I am getting better at them. I do wonder how one could possibly know normal ranges of all of them but standard panels aren't that hard. Just takes work...that I'm kinda too lazy to do right now... :lol:

Exactly. I look at labs everyday and I certainly don't know them all. That is precisely why I recommended first memorizing the most basic, common, and useful values. Most paramedics already have some idea of the physiology/pathophysiology behind the basic chemistry and CBC, so adding a knowledge of the normal ranges then gives you a foundation upon which to learn to interpret.

No. I see value, on the other hand, in paramedics being able to interpret basic labs, which is not the same as simply knowing the ranges. It's one thing to know the ranges (which I don't think is the same as being able to interpret them)

But how can one interpret basic labs if one doesn't even know what a normal value is vs. an abnormal one?

All I'm saying is that at a bare minimum, when a paramedic picks a patient up in the ED for transfer to another facility and is told "her K is 2.7" or "her hgb is 6", they shouldn't have to pull out an iPhone app or go rifling through the transfer paperwork to look at the reference ranges on the lab report to have some idea what that means. A hard copy of the lab reports often aren't even sent with the patient these days.

Obviously, the better one understands the pathophysiology and the more background info one has about the patient, the more useful lab data is, but one doesn't need to know a ton about the patient to know "low hgb = poor oxygen carrying capacity = higher risk for cardiac ischemia, etc.".

 

[Ridryder911]

Every Paramedic should have a good basic understanding of basic lab values and the rationale of the values and importance behind of the most common.

Dr Bledsoe discussed this years ago in EMS forums of the need of increasing general medical knowledge of the Paramedic.

I do find it funny for those that oppose any increasing in knowledge, as it was not that long ago ... I heard the same arguments about learning interperting XII lead ECG's. ...

R/r 911

 

[mycrofft]

Wow, lots of the big guns here posting. Thanks everyone. I ready the reviews on mosbys diagnostic and lab... and I think ill be picking it up.

In response to the argument (which was a misunderstanding as I think you both are actually agreeing) regarding paramedics reading lab values dont forget that there are medics from all over the world on here so what may be in scope or an expectation in one place may not be the same where you work. (I often see people arguing when it's obvious that its an American talking to a European) although I don't think was the case here.

One more question out of curiosity, does any profession other than dr/PA in your area hold the expectation of interpreting labs?

We had to have some grasp to get through out nursing degree practicals. Nurses working in specialized units absolutely need to know their labs.

 

[JPINFV]

I do find it funny for those that oppose any increasing in knowledge, as it was not that long ago ... I heard the same arguments about learning interperting XII lead ECG's. ...

I don't see anyone here advocating against increasing the knowledge base of paramedics. I just object to the idea that memorizing normal values means that someone can interpret lab values.

 

[Handsome Robb]

One more question out of curiosity, does any profession other than dr/PA in your area hold the expectation of interpreting labs?

Our flight crews do it every day. Our Community Health Paramedics also draw labs and do POC testing and base treatments off their findings.