You will never see my face or know my name. You probably won’t give much thought to what happens to your blood after your doctor says, “I think we need to run some tests,” and the phlebotomist draws it into the tubes with their colored tops. I know I never did, until I became a medical laboratory technologist.

Over the course of a normal day at the hospital lab, my coworkers and I process hundreds of patient specimens — everything from blood to bone, from sputum to spinal fluid. Twenty-four hours a day, 365 days a year, the specimens come to us from the hospital’s ER and ICU, from doctor’s offices and nursing homes, from the inpatients on the floors above us and from outpatients who walk in through the hospital’s doors.

Our work is essential to the practice of modern medicine: It gives today’s doctors a wonderful ability to know in minute detail, as their predecessors couldn’t, what is happening within your body.

Your doctor has ordered a complete blood count, or CBC. One of the most frequently ordered tests, it provides a wealth of information. It tells the number of white blood cells circulating in your blood, and what type of white cells they are. It tells your hemoglobin levels, the shape and size of your red blood cells and the number of your platelets.

The first time I become aware of you, it’s because of your white cell count.

My analyzer flags your specimen: The number of white cells is far higher than normal. A pair of human eyes must confirm the finding, so I inspect a drop of your blood on a microscope slide, smeared and stained to reveal your white cells.

There they are, forever frozen in time, their pretty (I think) purple-pink hue standing out clearly against a backdrop of red cells.

This is how I know, before anyone else, what your doctor only suspects: You have a left shift. This means one of three things: One, that your bone marrow is pushing out lots of new white cells in an effort to fight off an infection; two, that you have atypical lymphocytes, white cells whose contorted, scallop-edged shape suggests they are reacting to a viral infection; three, that you have something else that the pathologist will say needs follow-up testing when I send him the slide for review.

At some point, months down the road, your name becomes familiar to me. I know, even before I make a slide and look at it, that I can expect to have difficulty finding and counting your white cells. There will be only a few, and those few will look abnormal, because of your chemo treatments.

And even further on, when you are being admitted to the hospital often, my coworkers and I compare your lab values.

“Do you think this is right? Her hemoglobin has really dropped — how are the chemistries? What does the potassium look like? Should we get a redraw?”

Finally, your platelets fall to critical levels. There are none to count on my slide. I issue some red blood cells and platelets to a nurse, who transfuses you.

Later the nurse says, “She’s looking much perkier now.” This makes me happy; you’ll get to go home.

And then, one day, still in my pj’s, coffee in hand, I open the paper and check the obits (which is morbid, my husband reminds me).

I see your name and, finally, your face. And I learn details that I didn’t know before and that, because of HIPAA laws, I really couldn’t have known.

I have known you on the deepest and most intimate level — have known the minutest details of your cells. Now I also know that you served in the Marine Corps, that you were a Girl Scout leader, a softball coach, a mother and a devoted grandparent to many.

“Ohh,” I say out loud. I say your name.

At work, I say your name again.

“Did you see in the paper? Mrs. So-and-So passed away. You remember, with all the platelet orders?”

“Oh yes, I remember. I thought she was doing better.”

And then we stop for a minute, thinking about you.

Eventually we’ll go back to our microscopes and beeping electronic instruments. And my analyzer will flag someone else.

I will answer an ER doctor’s call: “Hey, I’m looking for CBC results on Mr. Such-and-Such … You got a white count for me?”

“Yes, I’m looking at the slide now.”

You may never think about me as I work in the lab. But I think of you, and wish you well.

Kristen Nace is a laboratory technologist. This piece was originally published in Pulse — voices from the heart of medicine, and is reprinted with permission.