[W2] Point of Care Testing in Diagnosis of Disease Flashcards
What is POCT?
The analysis of biological specimens outside of the general laboratory
What are the 5 alternative definitions for POCT?
- near patient testing
- bedside testing
- ancillary testing
- extra-laboratory testing
- decentralised testing
Why is POCT used?
Quick turn around time
- used to make quick decisions
- reduces hospital stay time
- patients moved to relevant wards faster
What are the 5 benefits to POCT?
- optimised drug treatment
- more appropriate use of drugs
- reduced use of blood products -Rotem
- reduced used of lab staff, equipment and space (depends)
- virtual wards/community care of frail/elderly patients so that they are treated in the comfort of their home
What are the 3 drawbacks of POCT?
- cost
- quality of results (most staff that use have no core professional experience) (require risk assessment)
- training and certification is very cumbersome (3000 operators vs a team of less than 10)
What must a business case for a POCT device include?
Budget allocation, sustainability, and cost over £10,000 must use an existing framework or tendering process.
What factors should be considered when choosing a POCT device?
Technology, ease of use, and affordability.
Who is involved in the verification of POCT devices?
Clinical scientists, biomedical scientists, associate practitioners, and admin staff.
What specialists are part of the POCT verification team?
H&S, IT, Quality, and training specialists.
Who requires training for POCT?
Doctors, nurses, allied healthcare professionals, and care assistants.
What is involved in the POCT rollout?
Device distribution and reagent procurement.
Who performs daily maintenance of POCT devices?
The POCT team or ward staff.
What is the role of the POCT Committee?
Overseeing development, implementing policy, and ensuring quality assurance.
What does the POCT policy ensure?
Proper maintenance, quality assurance, accurate recording, and user training.
Why should POCT procedures be considered hazardous?
They involve body fluids and are classified as “dirty” activities.
Where are many point-of-care tests performed?
At the patient’s bedside or in the doctor’s office.
What should be provided for POCT devices used in general locations?
A designated area for device storage and essential consumables.
Where can small, portable POCT devices be placed?
On a trolley or worktop.
What facilities should be easily accessible for POCT device use?
Hand wash facilities and necessary IT equipment.
What physical barrier should a POCT room have if near patients?
A fixed solid screen between the benchtop device and patients.
What type of benching is required in a dedicated POCT room?
Continuous laboratory-grade benching with completely sealed joints.
How should walls be protected in a POCT room?
With a continuous plastic splashback from the benchtop to the ceiling.
Why should under-bench cupboards have no kickboards?
To allow easy cleaning and prevent contamination.
What hand hygiene requirement must be met in a POCT room?
Easy access to a hand wash basin with no doors between the POCT area and the basin.
What personal protective equipment must be available in a POCT room?
Dedicated gloves, goggles, and an eye wash kit.
What waste disposal facilities are required in a POCT room?
A clinical waste bin and a domestic waste bin.
What electrical and IT infrastructure should a POCT room have?
Adequate plug sockets, IT ports at bench height, and a protected power source or UPS for analysers.
What type of fridge is required if needed in a POCT room?
A laboratory-grade under-bench fridge with temperature monitoring.
What environmental controls are required in a POCT room?
Adequate lighting and climate control.
What restrictions apply to patient access in a POCT room?
Patients must not have access to the room.
What items must not be stored in a POCT room?
Sterile items, drugs, injectable solutions, food, drink, or clean clothing.
What procedures are prohibited in a POCT room?
No patient procedures should be carried out in the room.
What is required if consumables are stored in a POCT room?
A system for real-time storage temperature monitoring.
What factors should be assessed in a POCT risk assessment?
Process, reagents, chemicals (COSHH), staff tasks, and impact on patient results
What are potential risks in POCT related to sample handling?
Wrong sample, wrong patient details, pre-analytical and post-analytical errors.
How does sample quality affect POCT results?
Poor sample quality leads to unreliable results (“Rubbish sample, rubbish results”).
What ensures the accuracy of POCT results?
Internal Quality Control (IQC) and External Quality Assessment (EQA).
What is the purpose of quality control in POCT?
To detect and prevent systematic errors before they affect patient results.
What two factors can impact POCT reagent reliability?
Lot-to-lot variability (reagent drift) and reagent degradation.
What are the two types of POCT technologies?
Benchtop analysers and handheld devices.
How do benchtop analysers compare to laboratory analysers?
They are smaller versions of laboratory analysers.
What is the difference between qualitative and quantitative tests?
Qualitative tests provide a positive or negative result, while quantitative tests provide a numerical value.
What does reflection photometry measure?
The intensity of light at a specific wavelength to determine the concentration of a substance.
How does reflection photometry compare to spectrophotometry?
It is less comprehensive than spectrophotometry.
What chemical reaction occurs in glucose oxidase-based dry reagent chemistry?
- Glucose + O₂ → Gluconic acid + H₂O₂
- H₂O₂ + Leucodye → Dye
How do electrochemical glucose meters work?
Glucose oxidase transfers electrons directly to electrodes, generating an electrical current to calculate glucose concentration.
How do electrochemical glucose meters compare to reflection photometry?
They are more sensitive (require only 1 μl of blood) and provide results faster (within 5 seconds).
What is the principle behind spectrophotometry in blood gas analysis?
Measures light intensity across a range of wavelengths; absorption spectrum is used for oximetry.
What parameters are measured using spectrophotometry in blood gas analysis?
ctHb, sO₂, FO₂Hb, FCOHb, FHHb, FMetHb, FHbF, and ctBil.
How does potentiometry work in blood gas analysis?
Measures the potential of an electrode chain using a voltmeter, related to concentration via the Nernst equation.
What parameters are measured using potentiometry?
pH, pCO₂, K⁺, Na⁺, Ca²⁺, urea/BUN, and Cl⁻.
How does amperometry function in blood gas analysis?
Measures electrical current proportional to the oxidation/reduction of a substance at an electrode.
What parameters are measured using amperometry?
cGlu, cLac, and creatinine.
What is the principle behind optical pO₂ measurement?
O₂ reduces the intensity and time constant of phosphorescence from a dye in contact with the sample.
Which parameter is measured using the optical pO₂ method?
pO₂.
What biomarkers are measured using the Radiometer AQT90FP immunoassay?
D-dimer, CRP, and Troponin.
What are lateral flow tests and dipsticks commonly used for?
Pregnancy, drugs of abuse, HIV, SARS-CoV-2, etc.
What is PCR used for in POCT?
Detecting pathogens such as SARS-CoV-2, Flu A&B, and RSV (e.g., GeneXpert, Roche Liat).
What does rotational thromboelastometry (ROTEM) measure?
The haemostatic profile of whole blood.
How does ROTEM work?
A citrated whole blood sample is placed in a test cup with a suspended oscillating rod; clot formation impedes rotation, producing a graphical output (multi-TEMograms).
What do qualitative hCG test results indicate?
The presence of hCG but no additional pregnancy details.
What do quantitative hCG test results allow for?
Examination of pregnancy progression.
How do hCG levels change in a normal pregnancy?
They increase in a predicted fashion.
How do hCG levels behave in an ectopic pregnancy?
The expected increase is blunted or absent.
How do hCG levels change in a miscarriage?
They decline according to the molecule’s half-life.
What happens in denaturation of protein?
It leads to the shutdown of all enzymatic and metabolic processes, making life incompatible.
What is formed when H+ and CO2 combine?
Acid.
What does HCO3- represent?
Alkaline.
Which organs maintain acid-base balance?
The kidneys and lungs.
How is CO2 managed in the body?
CO2 is respired in the lungs.
How are H+ and HCO3- managed in the body?
H+ and HCO3- are absorbed and excreted by the kidneys.
