What's the big deal about the white blood cell count?

Pretty much every position I’ve worked in has had some teaching and the importance (or lack thereof) of the WBC often comes up in discussion with students and residents. Below is a summary of what I try to tell my trainees. It is not a complete description of how to use the WBC in clinical medicine, but it gives trainees a good start when understanding this test. I hope that students, residents, and other clinicians in teaching roles find this useful.

The WBC is a common test we acquire in clinical medicine. Some clinicians lean on it heavily for their clinical decision making. Other clinicians have the opinion that the WBC has little usefulness. What I teach my trainees is that the WBC is a valuable tool that has limitations.  We must understand its limitations to use that tool correctly.

Let’s take a step back and consider testing in general. Then let’s see how the WBC fits in this paradigm specifically. From a certain perspective, we have 2 kinds of tests, tests that:

1.       Help to define a diagnosis

2.       Measure severity of disease

The WBC generally falls into the second category, it’s a measure of severity. Outside of hematology, it’s typically not a test that gives us a diagnosis. Theoretically, any physical stress can elevate the WBC. A WBC value cannot tell you whether or not there is pyelonephritis, or pneumonia.

However, it can help us judge the severity of a pyelonephritis or pneumonia.

For example, consider

• a patient with pyelonephritis and a WBC of 16 and
• a patient with pyelonephritis with a WBC of 8

If all other aspects of the patient are equal, most clinicians would consider the first patient sicker.

The WBC is also useful to track progress of treatment. 

For example, in that same pyelonephritis patient with a WBC of 16, there

• is improvement if the previous day’s WBC was 20
• is worsening if the previous day’s WBC was 12.

A WBC is not a very good screening test either.

• A normal WBC does not completely rule out an inflammatory process. For example, a patient with appendicitis sometimes has a normal WBC.
• An elevated WBC does not always mean that an infection is severe. For example, strep pharyngitis can elevate WBC markedly.

The WBC is an imperfect test, neither perfectly sensitive or specific. To use the WBC wisely as the clinician, you have to see the big picture, the context that is the patient’s situation. Without the context, the WBC means very little. We need to use other tools to determine the diagnosis: the history, the physical exam, imaging, etc. We also have to use other data to help measure severity: heart rate, blood pressure, electrolytes, lactic acid, sedimentation rate, etc. For measuring severity of disease, the WBC is just one tool among several others that we often use in combination to give us a better understanding of the greater context.

If you’re interested about reading more about related topics such as the basics of making diagnoses, using laboratory testing, or teaching the topic of clinical decision making, please check out my book: A Guide to Clinical Decision Making.

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Tips for Dictating Your Chart

Recently, someone asked me for pointers to improve dictation. I realized that dictation was probably a less common now that in years past, and many new graduates had little or no experience with this skill.

I made a list of pointers based on research I’d done for my book, my previous blog post regarding written vs spoken English, my own experience dictating charts, and years of watching my mother dictate the charts she used to bring home from the office. I’ve summarized these points into this brief blog post.

The underlying concept to keep in mind as you dictate is that written English is not spoken English. You should not dictate your chart in the way you would speak. If you write the way you speak, your chart will typically be a lot less clear and a lot longer than if you wrote it. 

Remember that you want your reader to understand your story quickly and easily. A long, rambling, unfocused chart does no one any good. Well-thought out dictation can be just as good as a well-written chart at conveying the patient’s story efficiently.

Keeping these few points in mind will bring you a long way:

• ·         Take a moment before you begin to organize your thoughts.
• ·         Have a template ready in your mind if you have enough similar cas
• ·         Have a few notes in front of you to focus your dictation.
• ·         Use short, simple sentences whenever possible.
• ·         Put related thoughts together into paragraphs.
• ·         Avoid needless repetition.

If you’re interested in learning more about medical charting for clear communication, check out my book: The Handbook of Medical Charting

Should I Make My Chart Vague?

Too many times, I’ve heard my colleagues say, “I leave my chart intentionally vague so that no one can find anything wrong with it” or “I make my charts generic so that when I defend it the way I want to”.

These strategies can actually their authors open to the very assaults these strategies are supposed to protect them from.

Your chart is a record of your vision of that patient, of your side of the patient’s story. The record should stand apart from you. It should speak for itself. A well-written chart explaining the patient’s story should not need you to translate it. Ideally from reading your chart, your reader should see the patient as you saw the patient. Your reader should see the patient so clearly that they agree with you. The ideal happens rarely, but we should always try to improve.

Here are 3 fictional examples of how being too vague can potentially get you into trouble.

The drunk:

Your intoxicated patient is now clinically sober. You discharge him. He trips in front of the hospital and a bus runs him over. At autopsy his ethanol level is 200. Two versions of your re-assessment are below:

Vague: Clinically sober now.

Specific: Clear speech. Oriented x3. Cooperative. Calm. Finger to nose normal bilaterally. Walks tandem gait without stumbling.

When someone reviews the case later, do you want your chart to read vague or specific?

The fracture:

A patient comes into the ER for right leg pain. She is a nursing home patient with dementia. Your clinical evaluation finds no acute pathology. You discharge her. 1 week later she comes in for leg pain again. Evaluation finds a fractured, right femur.

A nursing home assessment from before her initial visit to you reads: “Contracted, thin extremities bilaterally. Hyperpigmented rash at bilateral ankles.”

Two versions of your initial exam are below:

Vague: Bilateral lower extremities normal.

Specific: Bilateral lower extremities have no bony point tenderness, no swelling, no bruising, no deformity.

When someone reviews your chart later, do you want your chart to be vague or specific?

The stroke:

A middle-aged patient comes in for dizziness. You find no concerning findings on your evaluation. 2 weeks later, outpatient workup reveals a posterior circulation stroke. Again, two versions of your exam are below:

Vague: normal neurological exam.

Specific: Walks on tip toes without stumbling. Negative Romberg. No nystagmus.

When someone reviews your chart later, which way do you want your chart to read, vague or specific?

Certainly we could all go into painful detail about every last detail. But consider:

What are the important parts of the story we want the chart to convey?

What details tell our patient’s story and which are needless?

If you chart with specific and concreter details, your chart will better protect you whether it’s from a patient complaint, a morbidity and mortality conference, or a legal proceeding.

Your chart should stand on its own. You should build it well to protect you. You should not have to protect it.

If you’re interested in learning more about improving your medical charting, check out my book: The Handbook of Medical Charting.