please help this LOST nursing student w/ laboratory studies!

hikernurse · Jun 5, 2008

I'm not so experienced at patients much older than brand new, but what you have said sounds good :).

Both of those results can indicate impaired renal processes. Erythropoietin is made in the kidney and is a strong stimulant of RBC's.

BUN is a rough estimate of renal function.

A book that helped me through care plans (and where the above quick info came from, sorry I'm in a rush to get my kids fed, bathed and in bed) is:

Mosby's Manual of Diagnostic and Laboratory Tests 2e by Kathleen Deska Pagana and Timothy J. Pagana.

It explains the test, possible reasons for highs/lows and a quick discussion of what the test is good for.

Interpretation comes along with experience :). You'll get there.

loricatus · Jun 5, 2008

I'll try to start you in the right direction...

Kidneys produce a hormone called Erythropoietin, which stimulates RBC production in the bone marrow. Kidney disease can affect Erythropoietin levels & therefore, RBC production...

lorenwithano · Jun 5, 2008

thanks so much!!!!

that honestly helped me a bunch!

i will have to check out that book and add it to my library of books ive purchased since nursing school.

thanks again everyone!

northwestwind · Jun 5, 2008

Your best reference is the patient's physician. If you are there during the time the physician is there, go up to them and ask them. They are the best teachers around - and they will help you out if you ask. They want RNs to understand this stuff, and many don't ever ask them. So get out there are ask them!

nursegreen · Jun 5, 2008

What was the patient's creatinine? If that was also high than I would say yes renal. If the BUN was high and the creatinine was within normal range I would think more along the line of dehydration. Low RBC's, I would say anemia, renal, cancer of bone marrow, and chemo. These are just a few....I'm sleepy. Remeber, always to look at your pt.'s H&P because a lot of times you will find something that will relate to your lab values. I will tell you that it eventually clicks. Just always pull your labs first thing after report, check them against meds, and notify MD of abnormal values. Before you know it you will be doing it without having to look up the parameters for lab values.Good Luck!!!

ann945n, RN · Jun 5, 2008

I would invest in a lab book. Hopefully the book store at your school sells them. It can give you some insight in how to interpret the test results. I also liked this site as a student http://www.labtestsonline.org/

core0 · Jun 5, 2008

hello everyone!
i am posting this question in both the general nursing discussion and student forum because quite frankly im a bit lost. my professor assigns every student a patient each week and were responsible to find their labs and interpret the patients values. great. easy. HOWEVER, when it comes to interpreting anything else im not sure if i have the hang of it.
my pt's RBC is 3.76 (low)... what could this indicate? i said it could indicate anemia. my pt. also has hyptertensive kidney disease, could this contribute to the low RBC?
now the one thats giving me the hardest time is the BUN.
my pt.'s BUN was 26 (high)... help help help! what could cause a high BUN? renal disease?? (she has hypertensive kidney disease)...
any help would be greatly appriciated!!! :) thanks everyone.
-loren

You really can't claim anemia based solely on RBC. Anemia is technically a deficiency in hemoglobin. If you look at the CBC there are three values that essentially measure the same thing in different ways.

RBC is the amount of red blood cells in one cubic millimeter. The number is millions.

Hemoglobin - this is the amount of hemoglobin (the compound that carries oxygen) in one deciliter measured in grams.

Hematocrit - this is the percentage of blood that is hemoglobin.

Generally the Hemoglobin should be around 1/3 of the hematocrit. The key is not to look at the RBC in isolation but in terms of the hemoglobin and hematocrit. If the RBC in low but the Hemoglobin is normal this may indicate that the cells are large but the overall level of hemoglobin is normal. This should be indicated in the size of the RBCs which is the mean corpuscular volume. The best indicator of anemia is the Hematocrit.

Here is a good explanation of the CBC as well as a list of some of the causes of deficiencies:

http://www.nlm.nih.gov/medlineplus/ency/article/003642.htm

Like the hemoglobin and hematocrit the BUN and creatnine are in someways different measurements of the same value. Both measure renal function among other things.

BUN is Blood urea nitrogen. Urea nitrogen is a waste product of protein metabolism. It is processed by the liver and excreted by the kidneys. Because of this it can be used to measure kidney function since it rises as the kidneys fail. However, it is less reliable than creatnine since high protein diets can cause elevated BUN. GI bleed can also cause increased BUN for example as the protein in the blood is digested. A classic GI bleed presentation is a low hematocrit high BUN and normal creatnine. A high BUN with a normal creatnine is usually either increased protein intake or increased protein catabolism.

Here is a nice explanation:

http://www.rnceus.com/renal/renalbun.html

Creatnine is the other part of kidney function. This is a non protein waste product of skeletal muscle metabolism. It is a continuous product and good for a quick and dirty measurement of renal function. A couple things to remember. Creatnine is logrhythmic so a change of 1 to 1.5 is a much worse problem than a change to 2 to 2.5. Also it can be lower is people with muscle wasting which can lead you to underestimate the amount of renal damage.

here is a good explanation:

http://www.rnceus.com/course_frame.asp?exam_id=13&directory=renal

This issue with interpreting lab values is that you have to interpret this in the context of the other labs. What is the RBC in relation to the hemoglobin? If they are both low then that is anemia (although anemia is a symptom not a cause). Probably secondary to your patients kidney disease. If the H&H is normal then you have to look at other causes. Are the other indices abnormal (size for example)?

In the case of BUN what is the creatnine? If they are both elevated then the BUN is probably secondary to the kidney function again. If the BUN is elevated but the creatnine is normal then you would consider a high protein diet for example (not a good idea in a renal patient).

It takes a lot of practice to be able to rapidly interpret labs. Try to understand them in the context of the disease and in relation to each other.

Good luck

David Carpenter, PA-C

lorenwithano · Jun 5, 2008

i actually HAVE been checking out that website and its been a great help!!!!!!

lorenwithano · Jun 5, 2008

thank you everyone! its really starting to click. the more practice i have and the more i really look into the labs i should start to "get it".

thanks for your time! :)