help with lab interpretation...

[pjcraw]

Hello!

I am reviewing some labs and have hit a wall on a particular lab. I'm probably overly worried about it, but I would really appreciate any input!

This is an elderly patient that has history of heart failure and CAD. He was admitted for dyspnea.

Other abnormal or pertinent labs:

Troponin: WNL

CPK: HIGH

CPK-MB: HIGH

Albumin: LOW

H/H: LOW

All renal and liver tests WNL

Now, what I'm wondering about is his differential and absolute counts.

They are actually all considered WNL, but one of them is still bothering me, just because I want to know what caused the change:

Day 1 abs lymphs: 2450

Day 2 abs lymphs: 1940 (this also showed in the differential with an increased %)

Day 3 abs lymphs: 2690

No major changes in Neuts.

Any ideas of what could have caused the drop in lymphs for just the one day? Like I said, I know it is still considered WNL, but it is still bothering me :)

Thanks! I appreciate your time!

[Double-Helix, BSN, RN]

I think that the value is within the normal variation for lab results. A little bit of dilution of the blood (too much saline, not enough blood) could cause a slight drop. This is particularly likely if the sample was drawn from an existing IV line that had fluid running through it. It could also be slightly diluted if the patient had just received a bolus of fluid.

[EricJRN, MSN, RN]

When you're first getting into this stuff, the tendency is to think pretty concretely. I think that sometimes nursing school encourages this thinking that every single lab and assessment finding must have a specific and easily identifiable cause. What you'll learn is that labs are just one tool in your toolbox and that you can't really tell much about a patient without completely integrating each part of the patient's picture - symptoms, assessments, meds, labs and other studies.

I admire your persistence, but when you get into comparing a series of normal values, you're unlikely to be able to pinpoint specific causes of these small decreases. Was it an exposure to a viral illness? A response to a random med? A technical issue with the phlebotomy? A quality control issue with the lab technology? Who knows? In the real world, with no mention of any change in the patient's status, this isn't something that we would hone in on.

One minor point is that a differential is the section of the CBC that counts and compares the different types of white cells. The two values that you see for each type of cell would be the absolute and relative values.

[pjcraw]

Thank you so much for taking the time to answer this! I had a feeling I was thinking about it too much :)