Hospital Labs: Behind the Scenes

The white-coated phlebotomist stops by your bedside to draw blood. Making sure the labels on the collection vials match your hospital ID band, she applies a tourniquet above the antecubital space inside your elbow, where the veins pop up nicely. You barely feel the venipuncture needle as she expertly slides it in. Your blood fills several tubes: a lavender top for a complete blood count, a red top for chemistries like potassium levels and a blue top to measure clotting.

"These'll go straight to the lab," she says, and you vaguely picture a roomful of dark countertops crowded with test-tube racks and microscopes. But in reality, most hospital laboratories are major departments, comprising multiple areas such as chemistry, microbiology, hematology, virology, histology, immunology/molecular diagnostics and the blood bank.

Today, highly automated labs process hundreds of samples a day, as medical laboratory scientists sort "panic values" from routine results. But unlike doctors and nurses, their essential work is done out of public view.

Critical Values

Everett Bloodworth, director of the laboratory department at Marshall County Hospital in Kentucky, has been delving into blood samples since 1970. (And he's heard enough puns on his name and line of work.) In this community hospital, the lab processes specimens from roughly 80 patients a day.

A new patient, pale and listless, complains of fatigue. The doctor orders routine blood work that turns out to be urgent. "A lot of times, people will be severely anemic, and they'll have gone down so slow that their body adjusts," Bloodworth says. "And they walk into the ER and they've got a hemoglobin of 5, and it's supposed to be 10." Patients like these get a transfusion "pretty quickly," he says.

Lab orders from the ER go to "the head of the line," Bloodworth says. Urgent results may involve glucose levels in patients with diabetes, where extreme highs and lows can be disastrous. Or heart emergencies: "Cardiac enzymes -- [doctors] want those fast, because time is heart muscle."

The lab team alerts medical staff when they pick up numbers that signal danger. "Those are critical values," he says. "If we have that 5 hemoglobin, or that 500 glucose, then we immediately pick up the phone. And we document in the medical record that we called. And when we called."

The most common tests are CBC, blood chemistry profiles and urinalysis for routine screening. Urinalysis often involves an extra step with women of childbearing age: a pregnancy test to make sure X-rays or abdominal surgery don't pose a hospital hazard. The lab analyzes specimens from outpatient feeder clinics as well.

Under the Microscope

Diane Davis, director of the Medical Laboratory Science Program at Salisbury University in Maryland, describes the rapid pace of busy hospitals labs that process hundreds of specimens during a single shift. In highly automated lab areas, a large portion of the testing is done by instrumentation, Davis says. The medical lab scientist often has only brief contact with each specimen, loading it off the instrument and quickly reviewing the results.

Some specimens require further analysis; for instance, the complete blood count. "Microscopy might be done when values are very abnormal," Davis says, in which the scientist stains a drop of blood that's spread on a slide and examines it for abnormalities such as sickle cell or leukemia.

While the pathologist -- the physician in charge of the lab -- may do the final review, Davis says, "The first person to recognize leukemia is the person who's been sitting there looking at that slide."

Medical laboratory scientists -- the updated term for medical technologists -- do their work in relative anonymity. "There's like this whole hidden arena of chemical fume hoods and biological safety cabinets," Davis says. "People in anatomical pathology with scalpels in their hands, dissecting tumors that were just removed. And that's not something up front and center on anybody's ability to see. But nonetheless, it's crucial."

All Sorts of Specimens

Medical lab scientists "culture just about every spot on the body you can think of, and every fluid," Davis says, including some you might not realize you had. Less-common exams include pericardial fluid (around the heart), pleural fluid (around the lungs), amniotic fluid from amniocentesis and synovial (joint) fluid.

Meanwhile, throat swab cultures are common, and when it comes to body fluids, blood and urine are the big two.

Spinal taps are far more invasive, riskier procedures, done much less frequently. There has to be a "jolly good reason" to tap someone for spinal fluid, Davis says. "Generally, when those come through the door, you know someone's very sick, so you reprioritize what you're doing to grab onto the spinal fluids."

Hot-Button Infections

Recognizing infectious organisms such as antibiotic-resistant bacteria and tuberculosis, or rare cases of anthrax, are part of the job. With highly contagious organisms such as MRSA and TB, medical lab scientists alert the unit staff to put the patient on isolation.

Needle-sticks and body-fluid splashes are potential job hazards. For bugs such as MRSA or TB, "If you wear your gloves and do the things you're supposed to, the transmission rate to health care workers is fairly low," Davis says. But Ebola, while fortunately very rare in U.S. hospitals, "is a whole other critter in terms of transmissibility," she notes.

Besides the standard lab coats and gloves; face masks and shields, gowns, goggle and foot covers are used as needed. Labs contain several types of protective equipment, Davis says, such as "biological safety cabinets for infectious organisms, chemical fume hoods for chemicals, and downdraft hoods in the histology lab."

Evolution of a Specialty

The professionals who work in hospital labs have a bachelor's degree or more in the specialty of medical laboratory science. ( Clinical laboratory technicians who assist in the lab have different requirements.)

Medical lab science has come a long way from when Bloodworth started more than 40 years ago, when medical technologists (as they were then called) did lab work by hand in glass test tubes. He's excited about the "next wave" of molecular tests, with DNA testing of tumors that lets doctors know which drugs will work better for individual patients.

"Some 70 percent of health care decisions have some component of lab testing in them," Davis says. "Even if folks are just getting laboratory tests just to make sure they're normal; that in of itself is informing the decision of the clinician."

While Bloodworth jokes that he's been doing this work "way too long," he clearly enjoys it. And it doesn't have to be spotting some exotic organism. "Somebody's lab work looks normal, and you do a urinalysis and all of a sudden you realize they've got a kidney infection. You've found the reason they're sick, and it's easy to fix." It's satisfying, he says. "You're part of the solution."

Lisa Esposito is a Patient Advice reporter at U.S. News. You can follow her on Twitter, connect with her on LinkedIn or email her at lesposito@usnews.com.