Point of care testing

Dr. Kamal Modi

Definition

When a test is performed at a time At which test results enables a decision to be made

And an action taken That leads to an improved health outcome.

patient

doctor

request

phlebotomy

transport

register

prepare

analysis

Quality control

validate

report

transmit

interpret

AdvantagesReduced turn around time

Improved patient morbidity & mortality Reduction in hospital admission

Improved interaction between patient and carer

Reduction in clinical visits

Improved cost of care

Reduction in administrative work associated With test requesting & reporting

Disadvantages

Increase in administrative work associated with training andCertification of operators

Caregivers required to perform test

Increased risk of errors

Classification of types

Single use Multiple use quantitative Cartridge/ bench-top devices

Qualitative cartridge/strip

Quantitative cartridge/strip

With reader device

Analytical Principle

Reflectance

Lateral flow or flow through immunoassays

Electrochemistry

Electrical impedance

Reflectance

e.g.

Urine and blood dipsticks for glucose and various other analytes.

Electrochemistry

Strip deviceCassette and bench-top device

Glucose strip

A. Electrode sensorsB. Separating layer

Principle of Electrochemical Glucose strip

Glucose meter

A negative voltage of –0.4 V is applied at the reference electrode. When blood or a glucose solution is placed in the strip, a chemical reaction occurs inside it, generating a small electrical current proportional to the glucose concentration

Bench-top Devise

Principle

Measurement of

PH, PCO2, PO2,

Electrolyte, Glucose,

Lactate.

Cassette device

Lateral flow immunoassays

It is a biological sensors in which the recognition agent is an antibody that binds to the analyte.

e.g. measurement of troponin T , myoglobin, and D-dimer.

Electric Impedance

• Based on Coulter principle

• As fluid containing particles or cells is drawn through each micro-channel, each particle causes a brief change to the electrical resistance of the liquid.

• The counter detects these changes in electrical resistance.

• E.g. complete blood count

Unresolved Queries ???

Use of following principle in POCT

Light scattering / optical motion

Immunoturbidometry

Fluorescence

Multiwavelength spectrophotometry