HIDDEN HEALTH - PART 1: The culture club
Deep in the maze that is Surrey Memorial Hospital, hidden away from patients and visitors alike, is a critical cog in the medical machine.
While people will often hear doctors or nurses talk about sending something to the lab, they’ve never seen the place responsible for assisting in nearly three-quarters of patient care decisions made in a hospital.
At SMH, the lab is a busy place occupying two floors with its six departments: Medical Microbiology, Medical Biochemistry, Hematopathology, Anatomical Pathology, Transfusion Medicine and Accessioning.
In the Microbiology Lab, Heather Kelly, 38, is one of the people in the yellow jumpsuits handling the fluid samples that come from patients.
Samples of what?
“My kids say the poop and the pee.”
In more technical terms, it’s urine, stool, blood, lung fluid and various human tissues – swabs of animal bites, surgical sites, even placentas.
Kelly is a bacteria grower.
She gives the example of Strep throat, caused (usually) by a Group A Beta-hemolytic Streptococcus.
“You’ve got a sore throat, you go to the doctor and he takes a swab. He sends it to me, I put it on a plate the first day and it gets incubated.”
The next day, she has a look at it.
“From this, I’m going to decide what’s important” - she must differentiate the “bad” bacteria from the “good” normally found in a throat culture.
“Our job is to isolate the bad bacteria – the stuff that’s going to cause you problems.”
Although the 10-centimetre wide covered plates she handles look colour-coded with different shades of red, pink or brown, what gives them the colour is the growing medium on which the sample is placed.
“Chocolate grows tons of bacteria,” Kelly says, holding a brown plate of blood agar, a jelly-like composite of seaweed and mammal blood – named “chocolate” for its colour, not composition.
Another common one is MacConkey agar, used to grow gram-negative bacteria.
Photo: Heather Kelly grows bacteria for a living at Surrey Memorial Hospital. The samples? Her kids call them ‘the poop and the pee,’ but in more technical terms, it’s urine, stool, blood, lung fluid, various human tissues, swabs of animal bites, surgical sites – even placentas.
Depending on the predicted microbe types, or the “bad” bacteria being isolated, the plates are put into aerobic (oxygen), anaerobic (no oxygen) or carbon dioxide incubators. Specific pathogens are identified by their shapes as they grow, usually in 24-48 hours. (The lab’s protocol for urine is 24 hours; lung samples can take seven days or longer to incubate.)
Many of the bugs are easy for lab veterans to identify and will all look different from each other on the plates: Blobs, fuzzies or swarms, for lack of better terms. Some look like ground glass, others hemolytic with distinct circles around them.
Under the microscope, individual bacteria are usually either the shapes of balls (gram-positive, often given the suffix “coccus”) or rods (gram-negative bacillus), with some exceptions.
“E. coli, for example, is a pink stick – a gram-negative rod,” Kelly explains.
For urine samples, after a growth period, Kelly will visually (without a microscope) count the number of E. coli colonies per millilitre to determine if there’s a problem.
Experienced lab technologists also use their noses.
Pasteurella, a bacteria associated with pet bites, smells like wet dog.
Pseudomonas, a green, rod-shaped bug associated with water-bourne diseases, smells like grape.
Anaerobic bacteria such as those linked to gangrene are notorious for their foul odour.
Bacteria the lab techs aren’t sure of or want to confirm will go through an analyzer, which can ID a bug in four hours and the bug’s antibiotic susceptibility in 12 to 18 hours – the latter, in the report, allows doctors make better choices about which antibiotics to use for specific pathogens.
“The lab helps in about 70 per cent of diagnoses of patients,” Kelly says.
For certain tests doctors request, such as C. difficile, the lab turns to the new Polymerase Chain Reaction (PCR) instrument, which copies and analyzes DNA fragments of small samples.
“It’s a very big deal to us,” says Kelly.
Able do its job in about two hours, the PCR is the most high-tech piece of equipment in the lab.
(A sample of a worst-case unknown pathogen would be sent to the BC Centre for Disease Control in Vancouver – an extremely rare occurrence).
Even with the high-tech methods available to her, Kelly, who has worked at the SMH lab since 1995, likes the tactile nature of her job.
“That’s why I chose microbiology as opposed to chemistry and hematology. Personally, I have no interest in sitting in front of an analyzer letting the thing spit out your sodium levels. I like piles of stuff... colours and smells.”
Surrey Memorial Hospital’s lab has six departments:
• Medical Microbiology, which tests for bacteria and related pathogens, and tests their sensitivity to antibiotics;
• Medical Biochemistry, which tests blood and other fluids for cholesterol, sodium, tumour markers, proteins and enzymes;
• Hematopathology, which tests red and white blood cells for disorders such as anemia and leukemia;
• Anatomical Pathology, which tests tissues, often for cancers;
• Transfusion Medicine, which tests for blood compatibility; and
• Accessioning, which takes in collections of blood for recording, pre-analytical testing, spinning and separation of serum for testing in other sections of the lab.
The SMH lab analyzes more than 3,000,000 samples per year. The microbiology lab alone, responsible for about 84,000 local tests each year, also takes in collection from other hospitals that don’t have their own microbiology labs: About 24,000 from each of Peace Arch and Langley Memorial hospitals and about 7,000 from Delta Hospital.
Sherry Warren, manager of Laboratory Medicine at SMH and the Jim Pattison Outpatient Care and Surgery Centre, oversees the lab’s staff of 165 technologists. Activity peaks with about 70 on duty during the daytime.
Though the lab plays a critical role in patient-care decision making, Warren describes its two floors as “a big black box in the middle of the hospital” that many nurses haven’t even seen.
“We’re very much an integral part of any patient that walks in the door,” she says. “We do a lot of important work and have very dedicated staff.”
In 2014, five of the lab’s six departments will move into an “open concept” lab on the fourth floor of the new Critical Care Tower being built at SMH. Only Anatomical Pathology will remain where it is – close to the morgue.
Next week: The interpreters
A small group of doctors makes critical diagnostic evaluations
More in the series: