POCT Flashcards
Specimen analysis performed outside of the clinical laboratory setting
Point of care testing
immediate results can be delivered, allowing assessment and management to be given swiftly.
point of care testing
POCT can be done at ___
(the 3 places it is possible to conduct)
BPO
- bedside of the patient
- physician’s office
- or any alternative site
Other names for POCT
● near patient testing
● Bedside testing
● Remote testing
● Satellite testing
● Physician’s office testing
● Extra-laboratory
● Decentralized
● Ancillary
● Alternate site testing (AST)
● Rapid diagnostics
ways in conventional testing procedure
- patient arrival
- collect sample
- sample procedures
- perform test
- compile all results
- analyze result
- patient admitted or discharged
ways in poct
- patient arrival
- Collection of sample
- Load the sample
- Analyze result
- patient admitted or discharged
Advantages of POCT
(CURSER CAR)
- cheaper and quicker traditional diagnostic methods.
- Can be used in resource limited settings
- Reduced preanalytical and post analytical testing errors
- Easier to use and reduced the need of training
- Rapid data availability
- Reduced the patient’s length of stay and waiting time in the hospital
- Convenient for clinicians
- Ability to test many types of samples
Disadvantages of POCT
BCDNQ
- Concerns about inaccuracy, imprecission, and performance
- Quality in testing is operator-dependent
- Bedside laboratory testing is performed by poorly trained non-laboratorians
- Difficult in integrating the test results with HIS and LIS; lack of connectivity
- Narrower measuring range for some analysis
what is the ASSURED (REASSURED) criteria by WHO
R - real-time connectivity
E - ease in the collection of the specimens
A - affordable
S - sensitive
S - specific
U - user-friendly / simple to perform
R - robust and rapid
E - equipment free
D - deliverable to those who need the test
3 primary stages of POCT
- preanalytical
- analytical
- post-analytical
Occurs before running the POCT on a sample; this includes collection, transport, preparation, and loading
preanalytical
actual testing of POCT is conducted
analytical
it is the actual testing of a sample
analytical
begins when testing is complete,
and an obtained result is available
post-analytical
Two ways of communicating the results:
- Results can be communicated directly to the hospital’s database / HIS
- Results can be commu updated directly through written or verbal communication
What ate the specimen requirements and procedures:
- Adhering to personnel regulations
- Patient identification
- Patient preparation
- Preparation of specimen collection containers
- Patient compliance
- Accurate clinical documentation
- Proper specimen storage
- Proper technique in collecting the specimens
Pre-analytical errors
(7)
Lack of preparation of the patient
Lack of information about the patient’s condition
Inappropriate specimen technique
Wrong or missing additives to blood
Mislabelled/Mishandling of patient specimen
Specimen contamination
Degradation of specimen due to delays in specimen processing
Post-analytical errors
Misreporting the patient result
Recording the wrong patient test result
Lost Data
Delayed reporting of critical results
Factors influencing these errors and problems
include the
- setting and the
- extent to which the instrument is within a network
Things irrelevant for POCT.
1.Transport
2.storage
3.centrifugation
It is mostly unnecessary, as whole blood is used.
Evaluation of the test results
The greatest importance in the pre-analytical process.
Correct Collection of the Sample
POCT DEVICES
- Commercial Benchtop Devices
- uPADS
- Microfluidic Multifixed Devices
- Stand-alone POC Devices
- Smartphone-based Devices
- Commercial Handheld devices
Beta-hydroxybutyrate detection from whole blood sample
uPADS
Multianalyte antibiotic detection from plasma
sample
Microfluidic multiplexed devices
Nucleic acid amplification test from nose swab
samples with colorimetric readout
Stand-alone POC Devices
semen analyzer for male infertility
Smart-phone based devices
Drug abuse detection and Disposable cartridges
for saliva sample
Commercial Handheld Devices
POCT is accomplished using
portable devices
Many point-of-care test systems are in the form of and often enclosed in
easy-to-use membrane-based test strips, in plastic test cassette
Parameter: HCG(human chorionic
gonadotropin)
Sample: Urine, Serum
Pregnancy Test Kits
Parameter: Ascorbic acid, glucose, bilirubin, ketone, SG, blood, pH,protein, urobilinogen leukocytes, nitrite
Sample: Urine
Urine dipstick analysis
Paramter: Albumin
Sample: Urine
Microalbumin screening
Parameter: Group A Strep,
Influenza A, +B, HIV, Chlamydia trachomatis antigen, MRSA, Helicobacter pylori-specific IgG
antibody
Sample: Swab, Serum
Infectious Agents Detection
Parameter: Hemoglobin
Sample: Stool
FOBT
(fecal occult blood test)
A wide range of devices, including single pad urine tests (dipsticks) and test kits.
SINGLE-USE QUALITATIVE STRIP OR CARTRIDGE
AND/OR STRIP DEVICES
These are generally dried, porous matrices with impregnated carrier elements that
interact with the analyte(s) when exposed;
chemical reaction usually results in a color
change
Dipsticks/Urine Strips
This utilizes a layer of supporting
materials, such as porous paper of cellulose fiber
filters or woven meshes; example is the at-home
pregnancy test
Test kits
PARAMETERS REACTION TIME
1. Glucose, Bilirubin
2. Ketones
3. Specific Gravity
4. pH, Protein, Blood,
Urobilinogen, Nitrite
5. Leukocytes Esterase
- 30 seconds
- 40 seconds
- 45 seconds
- 60 seconds
- 120 seconds
This kit uses antibodies to detect human chorionic gonadotropin (hCG)
Pregnancy test kits
a hormone that can be
detected in the urine
hCG (human chorionic gonadotropin)
What is the specimen and principle for Pregnancy test kits?
Specimen: first morning urine ( concentrated sample)
Principle : Lateral flow technology
This line utilizes a combination of antibodies including a monoclonal hCG antibody to detect elevated levels of hCG
Test Line
This line composed of goat polyclonal
antibodies and colloidal gold particles.
Control line
This test kit detects hepatitis B surface antigen in human
serum or plasma
HBsAg Test Kit
HBsAg sample and principle
Sample: Serum/Plasma
Principle: Sandwich immunoassay
A lab test used to check stool samples for hidden
(occult) blood.
Fecal Occult Blood Test
Occult blood may indicate
Colon cancer or polyps in the rectum or colon
TRUE OR FALSE
Can detect the presence or absence of
blood – it can determine what’s causing the
bleeding
false
Can only detect the presence or absence of
blood – it cannot determine what’s causing the
bleeding
They include a meter or monitoring device thereby enabling for the detection and quantification of
analytes.
○ EX. Glucometer
SINGLE-USE QUANTITATIVE CARTRIDGE AND
STRIP TEST WITH MONITORING DEVICES
Done to evaluate warfarin (vitamin K antagonist)
and heparin therapy
Coagulation monitoring
Common coagulation tests checked:
PIAPA
○ Prothrombin time (PT)
○ International normalized ratio (INR)
○ Activated partial thromboplastin time (APTT or
PTT)
○ Activated clotting time (ACT)
○ Platelet function
Coagulation POCT Devices
Cascade cassette
CoaguCheck Xs Plus
GEM Premier 4000
iSTAT
Verify now
For what kind of test:
Cascade cassette
CoaguCheck Xs Plus
GEM Premier 4000
iSTAT
Verify now
Cascade cassette - ACT, APTT, INR/PT
CoaguCheck Xs Plus - INR/PT
GEM Premier 4000 - ACT, APTT, INR/PT
iSTAT - ACT, INR/PT
Verify now - Platelet function
A non-instrumented test ordered by the physician to evaluate capillaries for platelet plug formation.
Bleeding Time
Used for pre-surgical screening and detection of
problems involving hemostasis.
Bleeding Time
Methods in bleeding Time
(DICS)
○ Duke method (finger and earlobe)
○ Ivy method
○ Copley-Lalitch Immersion Test (uses sterile
Normal Saline Solution and 37 degrees Celsius
waterbath)
○ Surgicutt method
The common methods in bleeding Time
Duke’s method and surgicutt
Duke’s method:
● Patient pricked with special needle/lancet.
● Preferably on earlobe/fingertip.
● Swabbed with alcohol first.
● Prick depth: 3–4 mm.
● Patient wipes blood every 30 seconds with filter
paper.
● Test stops when bleeding stops.
This analysis has a prospective influence on patient
care than any other laboratory determinants.
ABG - arterial blood gas
are the most important factors in the
management of critically ill patients.
Tissue oxygenation
Ventilation
Acid base status
Parameters of ABG
pH
pO2
pCO2
refers to the concentration of hydrogen ions in
a solution.
pH
is an indicator of how well air is
exchanged between the blood and lungs;
measure of the pressure exerted by dissolved
CO2 in the blood plasma in proportion to the PO2 in the alveoli.
pCO2
pressure exerted by dissolved O2 and the
ability of the lungs to diffuse oxygen through the
alveoli.
pO2
placed on ice and held at
0°C until analysis
arterial blood
2 devices for blood gas analyzer
EPOC Critical Care Blood Gas Analyzer
OPTI Critical Care Analyzer
cartridge-based analyzer with all the analytical
requirements for the performance of a test contained
within an individual cartridge.
iSTAT
What are the tests offered by iSTAT?
Lactate
Hematology
Chemistries and Electrolytes
Cardiac Markers
Endocrinology
Blood Gases
Coagulation
CG4+
Lactate
CG8+, EG7+
Hematology
CHEM8+, EG7+
Chemistries and Electrolytes
cTnL, CK-MB, BNP
Cardiac Markers
Beta - hCG
Endocrinology
EG7+, CG8+
Blood Gases
PT/INR, ACT kaolin, ACT Celite
Coagulation
Most comprehensive device for POCT
iSTAT
Connects to LIS then transmits to EMR
iSTAT
transmitting nerve impulses
○ Hypernatremia (increased Na levels);
Hyponatremia (decreased Na levels)
Sodium
helps in nerve conduction and muscle
function; regulates acid-base balance and osmotic
pressure (STAT).
○ Hyperkalemia and Hypokalemia
Potassium
maintains the integrity of the cells by
helping in balancing osmotic pressure and acid-base
and water balance of the body.
○ Hyperchloremia and hypochloremia
Chloride
helps transport CO2 from the
lungs resulting in the reduction of hydrogen ions and increase in blood pH.
Bicarbonate ion
helps in muscular function,
cardiac function, blood clotting, nerve transmission function of the body.
○ Hypercalcemia and Hypocalcemia
Ionised ion
What are the steps to operate iSTAT?
- Insert 2 to 3 drops of blood into the cartridge
- Close the cartridge and insert it into the iSTAT handheld
- View the results on the handheld screen within minutes
- Upload information automatically to the HIS/LIS
iSTAT System Integration with LIS/EMR
iSTAT (if wireless transfer) > POC Data Manager > LIS > EMR
iSTAT > iSTAT Downloader > POC Data Manager > LIS > EMR
What are the 4 non-invasive POCT?
- Pulse oximetry
- Transcutaneous Measurement of Bilirubin
- Non-invasive hemoglobin monitors
- GlucoWatch BIOGRAPHER
For monitoring a patient’s oxygen saturation.
Pulse oximetry
Most common used sites for application for pulse oximetry
Fingernail and toenail beds
Principle for pulse oximetry
based on the red and infrared light
absorption characteristics of oxygenated and
deoxygenated hemoglobin
What is the particular wavelength for deoxygenated and oxygenated hemoglobin for pulse oximetry
Oxygenated- 940 nm
Deoxygenated- 660 nm
This meter measures the yellowness of the
subcutaneous tissue by measuring the difference in the optical density of two wavelengths through the skin
Transcutaneous Measurement of Bilirubin
What are the sites used in measuring transcutaneous Measurement of Bilirubin?
Baby’s forehead or sternum
A pulse co-oximeter that uses a multi-wavelength
sensor for spot check and continuous measurement
Non-invasive hemoglobin monitors
The technology emits multiple wavelengths of light and then calculates the hemoglobin concentration based on the adsorption of light in the blood.
Non-invasive hemoglobin monitors
The device that extracts glucose through intact skin via reverse iontophoresis where it is detected by an amperometric biosensor.
GlucoWatch BIOGRAPHER
GlucoWatch BIOGRAPHER can provide glucose readings every ?
20 minutes for 12 hours
Gauge the effectiveness of
the thrombolytic therapy
being administered to
patients who have suffered
from heart attacks
Cardiac Troponin T
and Troponin I
(cardiac markers)
Measures the alanine
transferase (ALT) of patients
under lipid-lowering
medication.
Lipid Testing
Differentiates chronic
obstructive pulmonary
disease (COPD) and
congestive heart failure
(CHF)
B-Type Natriuretic
Peptide (BNP)
Detects and evaluates
infection, tissue injury, and
other inflammation disorders
(usually non-specific).
C-Reactive Protein
(CRP)
Diagnostic tool for diabetes
therapy monitoring.
Glycosylated hemoglobin
shows what a person’s
average blood glucose level was for
3 months before the test
Glycosylated Hemoglobin
Measures the volume of the
red blood cells.
Hematocrit
(or PCV - Packed
Cell Volume)
Checks the hemoglobin level
to manage patients suffering
from anemia (either due to
low RBC count or low Hgb).
Hemoglobin
Evaluates the severity of
lactic acid disorder and
stress response of the
patient.
Lactate
Checks contact with
allergens and determines if
the body has developed
antibodies.
Skin test
Detects the presence of
group A streptococci (S.
pyogenes for pharyngitis).
Strep testing
