[1] poct Flashcards
1
Q
what does POCT stand for?
A
point of care testing
2
Q
what is the definition of POCT
A
- specimen analysis is performed outside of the clinical laboratory setting
- testing done at ___ where immediate results can be delivered, allowing assessment and management to be given swiftly
– bedside
– physician’s office
– or any alternative site
3
Q
other names of POCT (10)
A
- Near patient testing
- Bedside testing
- Remote testing
- Satellite testing
- Physician’s office testing
- Extra-laboratory
- Decentralized
- Ancillary
- Alternate site testing (AST)
- Rapid diagnostics
4
Q
is it considered POCT if sa ambulance?
A
yes
5
Q
is it considered POCT if outside sa lab door?
A
yes
6
Q
conventional testing procedure vs poct
A
conventional testing procedure:
- patient arrival
1. triage
2. collect sample
3. sample processing
4. perform test
5. compile test results
6. analyze test results
- patient admitted/discharged
POCT:
- patient arrival
1. sample collection
2. load sample
3. analyze results
- patiend admitted/discharged
half of the time is saved by poct
7
Q
advantages of poct (9)
A
- Cheaper and quicker traditional diagnostic methods
- Can be used in resource limited settings.
- Reduced preanalytical and post analytic testing errors
- Small sample volume for a large test menu
- Easy to use and reduces the need for training.
- Rapid data availability
- Reduced patient’s length of stay and waiting times in the hospital.
- Convenience for clinicians
- Ability to test many types of samples
8
Q
disadvantages of poct
A
- Concerns about inaccuracy, imprecision, and performance
- Bedside laboratory tests performed by poorly trained non-laboratorians
- Quality of testing is operator-dependent
- Difficulty in integrating information system (HIS) test or results with hospital laboratory information system (LIS); lack of connectivity
- Narrower measuring range for some analytes
9
Q
(RE)ASSURED criteria by WHO
A
R = real time connectivity
E = ease of specimen collection
A = affordable
S = sensitive
S = specific
U = user-friendly/simple to perform
R = robust and rapid (results available in less than 30 minutes)
E = equipment-free
D = deliverable to those who need the test
10
Q
specimen requirements and procedures
3 primary stages in the POCT process
A
pre-analytical, analytical, post-analytical
11
Q
specimen requirements and procedures
pre-analytical
A
occurs before running the POCT on a sample; involves collection, transport, preparation, and loading
12
Q
specimen requirements and procedures
analytical
A
actual testing sequence of a POCT is conducted
13
Q
specimen requirements and procedures
post-analytical
A
begins when testing is complete, and an obtained result is available
treatment and management of patient diagnosis
14
Q
important pre- and post-analytical errors in poct diagnostic testing
pre-analytical errors (7)
A
- Lack of preparation of the patient
- Lack of information about the patient’s condition
- Inappropriate sampling technique
- Wrong or missing additives to blood
- Mishandling and/or mislabeling of patient specimen
- Specimen contamination
- Degradation of specimen due to delays in specimen processing
15
Q
important pre- and post-analytical errors in poct diagnostic testing
Post-analytical errors (4)
A
- Misreporting patient result
- Recording wrong patient test results
- Lost data
- Delayed reporting of critical results
16
Q
important pre- and post-analytical errors in poct diagnostic testing
analytical errors in relation to POCT (1-2)
A
- there is a problem with the machine
– low battery
– inability to turn on
17
Q
important pre- and post-analytical errors in poct diagnostic testing
Factors influencing these errors and problems include the ______ and the ______
A
Factors influencing these errors and problems include the setting (practice, hospital, etc.) and the extent to which the instrument is within a network (availability)
18
Q
important pre- and post-analytical errors in poct diagnostic testing
what is irrelevant for poct
A
Transport, storage, and centrifugation are irrelevant for POCT. Evaluation of the test material is mostly unnecessary, as whole blood is used
19
Q
important pre- and post-analytical errors in poct diagnostic testing
what is of greatest importance in the pre-analytical process?
A
Correct collection of the sample is of the greatest importance in the pre-analytical process
20
Q
important pre- and post-analytical errors in poct diagnostic testing
POCT devices (6)
A
-
commercial benchtop devices
– centrifugal discs
– cartridge-based -
commercial handheld devices
– drug abuse detection
– disposable cartridges for saliva samples -
uPADs
– beta-hydroxybutyrate detection from whole blood samples -
smartphone-based devices
– disposable microchip
– semen sample
– optical attachment -
microfluidic multiplexed devices
– multianalyte antibiotic detection from plasma samples -
stand-alone POC devices
– nucleic acid amplification test from nose swab samples with colorimetric readout
21
Q
technology
POCT is accomplished using ___
A
POCT is accomplished using portable instruments
easy to carry
22
Q
technology
many point-of-care test systems are in the form of
A
many point-of-care test systems are in the form of easy-to-use membrane-based test strips, often enclosed by a plastic test cassete
para dli ma contaminated with air (unlike urinalysis strips)
23
Q
POCT application
pregnancy testing
parameter (1) and sample (2)?
which sample is more confirmatory?
A
- parameter:
human chorionic gonadotropin (HCG) - sample:
urine, semen
semen is more confirmatory than urine
semen is more confirmatory than urine
24
Q
POCT application
urine dipstick analyses
parameter (9) and sample (1)?
A
- parameter:
ascorbic acid, glucose, bilirubin, ketone, SG, blood pH, protein, urobilinogen, leukocytes, nitrite. - sample:
urine
25
# POCT application
microalbumin screening
| parameter (1) and sample (1)?
## Footnote
what is the clinical significance(?) of the parameter?
* parameter:
albumin
* sample:
urine
## Footnote
* presence of albumin means is kidney is not filtering properly
* albumin is a fat protein and should NOT be in urine (usually reabsorbed)
26
# POCT application
infectious agents detection
| parameter (7) and sample (2)?
## Footnote
match the parameter to sample
group A strep, influenza A + B, HIV, chlamydia, trachomatis antigen, MRSA, helicobacter pylori-specific IgG antibody
* sample:
swab, serum
| MRSA - staph aureus; helibacte - GIT bacte that can withstand GI acidity
## Footnote
swab:
* influenza a + b
* MRSA
serum:
* helicobacter pylori-specific IgG antibody
27
# POCT application
fecal occult blood test (FOBT)
| parameter (1) and sample (1)?
## Footnote
for what
* parameter:
hemoglobin
* sample:
stool
| occult means hidden
## Footnote
* hemoglobin is the breakdown of RBC
* to check for colon cancer / bleeding / polyps
28
# POCT devices
single-use **qualitative** strip or cartridge and/or strip devices
| how do u know qualitative? what differentiates it from quanti?
## Footnote
examples?
a **wide range of devices**, including single pad urine test (dipsticks) and test kits
| quali - reference values (words); quanti - numbers (trace /25% + unit)
## Footnote
* dipsticks/urine strips
* test kits
29
# POCT devices
dipsticks/urine strips
| single-use qualitative strip or cartridge and/or strip devices
**generally dried, porous matrices** with **impregnated carrier elements** that **interact with the analyte(s) when exposed**; chemical reaction usually results in a **color change**
30
# POCT devices
test kits
| single-use qualitative strip or cartridge and/or strip devices
## Footnote
example?
utilizes a **layer of suppporting materials**, such as **porous paper of cellulose fiber filters or woven meshes**
## Footnote
example: home pregnancy test
31
# POCT devices
parameters + reaction time?
| dipsticks/urine strips
* ascorbic acid, glucose, bilirubin - 30secs
* ketones - 40secs
* specific gravity - 45secs
* pH, protein, blood, urobilinogen, nitrite, albumin - 60secs
* leukocyte esterase - 120secs
32
# test kits
pregnancy test kits
(*antibodies and antigen? specimen and principle?*)
| whats the 2nd line for?
## Footnote
considered ba first morning urine if first ihi nimo sa hapon?
* use antibodies to detect human chorionic gonadotropin (HCG), a hormone that can be deteeceted in the urine
* specimen: first morning urine (concentrated urine)
* principle: lateral flow technology (capillary motion)
| control region - to know if daot ba ang test kit or expired
## Footnote
well, yes
33
# test kits
how does a lateral flow test work?
## Footnote
what is a test line and control line?
analyte --> conjugate pad captures analytes --> membrane --> test line and control line catches antigens --> wick gets excess antigen
## Footnote
* **test line** - utilizes a **combination of antibodies** including a **monoclonal hCG antibody** to detect elevated levels of hCG
* **control line** - composed of **goat polyclonal antibodies** and **colloidal gold particles**
34
# test kits
HBsAg Test Kit
## Footnote
explain its principle
* detects hepatitis B surface antigen in human serum or plasma
* sample: serum/plasma
* principle: sandwich immunoassay
## Footnote
placement of antigen is sandwiched between 2 antibodies
35
# test kits
fecal occult blood test (FOBT)
## Footnote
what is the antigen?
* a lab test used to check stool samples for hidden (occult) blood
* occult blood may indicate colon cancer or polyps in the colon or rectum
* can only detect the presence pr absence of blood - it cannot determine what's causing the bleeding
| oh naur u have bleeding but idk what -- needs confirmatory test
## Footnote
hemoglobin
36
# poct devices
Single-use **quantitative** cartridge and strip test with monitoring devices
| do we take the blood dayon after puncture?
## Footnote
do we still callibrate or perform QC? how?
* They **include a meter or monitoring device** thereby enabling for the detection and **quantification of analytes**
| NO! wipe 1st drop of blood cus it may have skin fragments or alcohol
## Footnote
YES! naay strip para ana
37
# poct devices
Coagulation monitoring
| what is coagulation? what section ni usually?
## Footnote
common coagulation tests checked? (5)
Done to **evaluate warfarin and heparin therapy** using coagulation POCT analyzer
*basically checks blood*
| when blood clots; hematology section
## Footnote
1. Prothrombin time (PT)
2. International normalized ratio (INR)
3. Activated partial thromboplastin time (APTT or
PTT)
4. Activated clotting time (ACT)
5. Platelet function
38
# poct devices
coagulation poct devices (5)
| which ones can be used bedside?
## Footnote
ngano diay if naay coagulation problems? asa ni commonly makita?
1. Cascade POC – ACT, APTT, PT/INR
2. CoaguChek XS Plus – PT/INR
3. GEM Premier 4000 - ACT, APTT, PT/NR
4. iSTAT- ACT, PT/INR
5. Verify Now – platelet function
| coaguchek and istat
## Footnote
* abnormal clot formation --> stroke/pulmonary embolism
* diabetic ppl (taas ug sugar) - tendency dli mo clot ug tarong ang blood
39
# poct devices
bleeding time
| erm what about bleeding time?
## Footnote
what are the different methods?
* A **non-instrumented test** ordered by the physician to **evaluate capillaries for platelet plug formation**
* Used for **pre-surgical screening** and detection of **problems involving hemostasis**
| determines how long bleeding stops when masamad ka; bleeding time
## Footnote
* Duke method (finger and earlobe)
* Ivy method
* Copley-Lalitch Immersion Test
* Surgicutt method
40
# bleeding time
duke method
| um when should u start timer ???
## Footnote
what is abnormal bleeding time
start timer immediately after puncture
## Footnote
4min bleeding time --> prolonged --> low platelets --> capillaries of patient
41
# bleeding time
ivy bleeding time
| ref values??? and when do u start timer?
standard/naas manual: 40mmHg, 30secs clotting time
| start time immediately after 1st puncture
## Footnote
idk what 8min and 35 secs means
42
# bleeding time
copley lalitch immersion test
37 degrees C - same sa body temp, stop timer when bleeding stops
43
# bleeding time
surgicutt method
* IV method
* 40 degrees
* no lancets
* most standardized
* keloid
* clotting: 2nd drop
* bleeding time: ASAP
44
# poct devices
blood gas analyzer
| what are its parameters?
## Footnote
what is the sample and anticoagulant? nganong e check nato ni?
* checks arterial blood gas
* ABG analysis has a prospective influence on patient care than any other laboratory determinants
* Tissue oxygenation, ventilation, and acid-base status are the most important factors in the management of critically ill patients
* Sample is arterial blood placed on ice and held at 0 °C until analysis
| Parameters include pH, pO2, and pCO2
## Footnote
heparin (green stopper)
* respiratory alkanosis acidosis --> death
* CO2 out (hyperventilation) --> CO2 up, blood pH down (acidic, not good)
* arterial blood is bright red, veinous is dark red
* 90 degrees
* slows down cellular metabolism of cell so cells cant eat the O2
45
# blood gas analyzer
what is pH?
pH refers to the concentration of hydrogen ions in a solution
46
# blood gas analyzer
what is PCO2?
PCO2 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
47
# blood gas analyzer
what is PO2?
PO2 is **pressure exerted by dissolved O2** and the **ability of the lungs to diffuse oxygen through the alveoli**
48
# blood gas analyzer
examples of blood gas analyzer?
* EPOC Critical Care Blood Gas Analyzer
* OPTI Critical Care Analyzer
| still needs callibration
## Footnote
EPOC: cartridge --> ABG --> choose test u want to perform
OPTI: measures electrolytes, releases receipt
49
# poct devices
i-STAT
## Footnote
i-STAT system range of tests? (7)
A **cartridge-based analyzer** with all the **analytical requirements** for the **performance of a test contained within an individual cartridge**
## Footnote
* lactate (CG4+)
* haematology (CH8+, EG7+)
* chemistries and electrolytes (CHEM8+, EG7+)
* cardiac markers (cTnl, CK-MB, BNP)
* endocrinology (B-hCG)
* blood gases (EG7+, CG8+)
* coagulation (PT/INR, ACT Kaolin, ACT Celite)
50
# electrolytes
sodium
## Footnote
what do u call if too much/too little?
transmitting nerve impulses
## Footnote
* hypernatremia - too much Na
* hyponatremia - too little Na
51
# electrolytes
potassium
## Footnote
what do u call if too much/too little?
helps in nerve conduction and muscle function;
regulates acid-base balance and osmotic pressure
## Footnote
* hyperkalemia - too much K
* hypokalemia - too little K
52
# electrolytes
chloride
## Footnote
what do u call if too much/too little?
maintains the integrity of the cells by helping in
balancing osmotic pressure and acid-base and water
balance of the body
## Footnote
* hyperchloremia - too much Cl
* hypochloremia - too little Cl
53
# electrolytes
bicarbonate ion
helps transport CO2 from the lungs resulting in the reduction of hydrogen ions and increase in blood pH
54
# electrolytes
ionized calcium
helps in muscular function cardiac function, blood clotting, nerve transmission function of the body
## Footnote
* hypercalcemia - too much Ca
* hypocalcemia - too little Ca
55
# poct devices
steps? (4)
1. Insert two or three drops of blood into the cartridge.
2. Close the cartridge and insert into the i-STAT handheld.
3. View the results on the handheld screen within minutes.
4. Upload information automatically into the LIS/HIS.
56
i-STAT System Integration with LIS/EMR
| flow
i-STAT --> wireless transfer or i-STAT downloader --> POC data manager --> LIS --> EMR
57
# non-invasive poct
Pulse oximetry
| naur punctures
## Footnote
how does it work? ref values (hemoglobin)?
* For monitoring patient’s oxygen saturation
* Most common used sites for application are the fingernail and toenail beds
* Principle is based on the red and infrared light absorption characteristics of oxygenated and deoxygenated hemoglobin
| measures oxygenated/deoxygenated
## Footnote
hemoglobin senses red light
deoxygenated - 660nm
oxygenated - 940nm
58
# non-invasive poct
Transcutaneous measurement of bilirubin
| nganong dli magamit sa dli babies?
## Footnote
whats up with bilirubin and babies? also what principle forda poct?
* The meter measures the yellowness of the subcutaneous tissue by measuring the difference in the optical density of two wavelengths through the skin
* Measurements are taken either on the baby’s forehead or sternum
| conjugated na ang bilirubin sa non-babies = jaundice, pls get checked
## Footnote
* yellowness - bilirubin (e bulad ras init cus its light sensitive)
* measures unconjugated bilirubin
* the more bilirubin, the more light smth
* gestational age, body weight, skin color
**poct principle(?): optical spectroscopy**
59
# non-invasive poct
Non-invasive hemoglobin monitors
## Footnote
why do we need to measure hemoglobin?
* A pulse co-oximeter that uses multi-wavelength sensor for spot check and continuous measurement
* The technology emits multiple wavelengths of light and then calculates the hemoglobin concentration based on the adsorption of light in the blood
## Footnote
hemoglobin carries O2
Hgb down = O2 down (not good)
60
# non-invasive poct
GlucoWatch Biographer
* A device that **extracts glucose through intact skin via reverse iontophoresis** where it is detected by an amperometric biosensor
* Can provide glucose readings every 20 mins for 12
hours
## Footnote
veins n capillaries -- measuring glucose ?
61
other tests performed through poct?
* cardiac troponin T and troponin I
* lipid testing
* B-type natriuretic peptide (BNP)
* C-reactive protein (CRP)
* glycosylated hemoglobin
* hematocrit
* hemoglobin
* lactate
* skin test
* strep testing
62
# other tests performed through poct
Cardiac Troponin T and
Troponin I
## Footnote
whats this for?
Gauge the **effectiveness of the thrombolytic therapy** being administered to patients who have suffered from heart attacks
## Footnote
heart attack / myocardial infarction
63
# other tests performed through poct
lipid testing
## Footnote
whats this for?
Measures the alanine transferase (ALT) of patients under lipid-lowering medication
## Footnote
measures ALT (enzyme in liver)
cholesterol up, ALT down
64
# other tests performed through poct
B-Type Natriuretic Peptide (BNP)
Differentiates chronic obstructive pulmonary disease (COPD) and congestive heart failure (CHF)
65
# other tests performed through poct
C-Reactive Protein (CRP)
## Footnote
what section and is this specific?
Detects and evaluates infection, tissue injury, and other inflammation disorders
## Footnote
* clin chem + immuno sero
* non-specific (screening); still needs diagnostic/confirmatory test
66
# other tests performed through poct
Glycosylated hemoglobin
## Footnote
erm whats the difference between this and FBS?
Diagnostic tool for diabetes therapy monitoring
## Footnote
* HbAl-C
* this one takes 3 months while FBS takes like a day or smth
* more accurate than FBS
67
# other tests performed through poct
Hematocrit
## Footnote
what about hematocrit?
Measures the volume of the red blood cells
## Footnote
O2 down, bone marrow: RBC up, hematocrit up
68
# other tests performed through poct
Hemoglobin
## Footnote
whats this for?
Checks the hemoglobin level to manage patients suffering from anemia
## Footnote
anemia
69
# other tests performed through poct
Lactate
## Footnote
measures what?
Evaluates the severity of lactic acid disorder and stress response of the patient
## Footnote
lactate acid levels
70
# other tests performed through poct
Skin test
## Footnote
what about it
Checks contact with allergens and determines if the body has developed antibodies
## Footnote
derma diff
71
# other tests performed through poct
Strep testing
## Footnote
whats this for and where is it collected?
Detects the presence of group A streptococci
## Footnote
* bacterial pharyngitis
* collect sa tonsils, or uvula if wlay tonsils (basta dont collect sa tongue)
