McDevitt of Rice University in Houston
has developed a device, called a biotometer, that analyzes saliva samples, as
well as other body fluids, on board emergency vehicles. Like programmers developing apps for an iPhone, McDevitt’s
team has individual test cards customized for specific health conditions. Each
card can look for multiple biomarkers
associated with that condition.
The battery-operated analyzer weighs
in at just under five kilograms, making it
light enough to transport from place to
place. Working like an ATM machine, the
device reads information on the disposable test cards inserted into it. Each card
contains a series of wells packed with tiny
detection beads that act as microsponges
to collect the biomarkers of interest.
McDevitt and his colleagues are
already using the device to analyze spit
samples to find out whether patients
with chest pain are suffering a heart
attack. A drop of saliva obtained from a
gum swab goes onto the appropriate test
card and is placed in the analyzer. If the
saliva sample contains troponin T, a protein characteristic of a heart attack (it is
released into the blood when heart cells
die), the detection beads will emit a fluorescent color. The analyzer spots that
color glow in the beads and indicates
that the patient is indeed experiencing
a heart attack.
McDevitt says he hopes saliva-based
tests can detect heart attacks faster and
more accurately than traditional methods. Of the millions of patients who visit
emergency rooms with chest pain each
year, only about half of those suffering a
heart attack are immediately diagnosed
using the electrocardiogram. The others
must undergo additional testing, which
can take anywhere from 90 minutes to
several hours to process.
With the biotometer, clinicians could
make a diagnosis within minutes instead
of hours, McDevitt says.
The device is now being tested in a
clinical trial in Houston, directed by
Baylor College of Medicine cardiologists, to see how spit samples work in
conjunction with the EKG to diagnose
cardiac arrest patients. A second study
That frothy fluid in your mouth holds all kinds of clues to the body’s happenings.
Drug use Saliva can reveal drug use, whether for therapy or recreation.
Hormones commercial test kits gauge estrogen, testosterone and cortisol levels from saliva.
HIV The u.S. Food and Drug administration has approved a test that looks in oral fluid for
antibodies known to be present in people with hiv infections.
Age a recent study suggests that genetic clues in spit can pinpoint age to within five years.
Cancer messenger rNa signatures for breast and pancreatic cancer have turned up in saliva.
Heart disease The protein troponin T in spit may pinpoint people having heart attacks.
is in progress on emergency vehicles in
Within spitting distance
Currently being manufactured by Force
Diagnostics, a biotechnology firm in
Chicago, McDevitt’s device will be made
available for real-world applications
within the next few months. The first
units will be deployed for blood-based
testing, targeting HIV infection in
Africa. A 12-minute field test will replace
a two-hour lab version, McDevitt says.
Initial applications for spit-based tests
using the biotometer and other devices
may appear within two to three years.
Oral disease and gum disease tests will
probably come online first. Widespread
screening for conditions such as pancreatic cancer, breast cancer or heart attack
may occur within five years.
These developments and other findings from various labs are laying the
groundwork for a dramatic change in
disease treatment, McDevitt says, allowing clinicians to move from reactive to
As part of the heart attack trial, for
example, his group is collecting information on protein changes associated with
the risk of future heart attacks. Current
diagnostic methods can’t easily detect
the earliest stages of cardiac disease, he
says, so the findings open up the possibility of using the biomarkers in saliva, or
other body fluids, to detect health risks
months or years before they become
“I think we actually have a way to do
it,” McDevitt says. “We’re seeing this in
our trials right now.”
His optimism is supported by a study
published in the Oct. 25 Journal of
the American College of Cardiology. It
showed that adjusting therapy to con-
trol levels of the protein NT-proBNP in
the blood of heart patients could lower
the rates of arrhythmias, stroke and
heart attack. NT-proBNP is a known
marker of cardiac distress, and is already
detectable in spit. Because spit tests are
cheaper and easier to administer than
blood tests, clinicians might someday
use them to monitor such patients.
s D. T. Wong. “Salivary diagnostics.”
American Scientist. January-February
November 19, 2011 | SCIENCE NEWS | 29