Point of Care Testing
Access to rapid diagnostic results means appropriate treatment can be implemented quickly,
leading to an improved clinical or economic outcome.
Point of care testing (POCT) may be performed with or near to the patient, with the result being generated within a reasonable wait time. This means clinical decisions about next steps in the care of that patient, further tests or treatment pathways,
can be made very quickly.
POCTs are laboratory tests conducted outside of the laboratory, usually by appropriately trained non-laboratory staff. The tests can be performed in a range of locations such as the GP surgery, in A&E or in the community. A wide variety of people can perform point-of-care tests, including laboratory professionals, paramedics, radiologists, doctors, nurses, or other healthcare professionals. Some point-of-care tests may even be done by the patient. These tests are often referred to as "self-tests" or "home tests".
Although centralised laboratories offer a much wider range of tests and remain the mainstay of diagnostic testing, POCT can offer a rapid turnaround time with a potentially immediate impact on patient care.
Lateral Flow Assays
Lateral Flow Assays (LFAs) are commonly used in POCT. These simple devices can detect the presence of a target marker in a liquid sample such as blood, saliva, urine or a faecal sample extraction. They do not require specialist or costly equipment to perform the test or read the result. The tests are simple, economic and generally show results in around five to 30 minutes.
The image shows the principal of an LFA - specifically the IMMY Cryptococcal Antigen (CrAg) assay.
Typically, the LFA consists of a sample pad, a conjugate pad, a nitrocellulose strip that contains test and control line/s and a wicking pad.
The overlapping of each component enables smooth capillary flow of the sample. Once sample is applied on the adsorbent sample pad, it migrates to the conjugate release pad containing antibodies specific to the target analyte and conjugated to fluorescent or coloured particles, usually latex microspheres or colloidal gold.
The sample containing the conjugated antibody bound to the target analyte migrates along the strip into the detection zone that contains antibodies or antigens immobilised in lines. These components react with the analyte bound to the conjugated antibody. Positive test line indicates recognition of the sample analyte while the response on the control line demonstrates proper liquid flow through the strip. The intensity of the appearing lines can be assessed either by eye or using a dedicated reader. After the control line, the sample flows into the wicking pad which maintains the capillary force and the flow of the liquid.
Lateral flow assays may be in a dipstick format or housed in a cassette. Both dipsticks and casette tests work in a similar way.
Alpha Laboratories supports your Point of Care Testing requirements with a range of assays for inflammation, bowel disease detection, infectious diseases and pregnancy testing.
C-Reactive Protein (CRP)
CRP is produced by hepatocytes upon stimulation by the pro-inflammatory cytokines IL-1α, IL-6 and TNFα, so is useful as a marker for inflammation. In diagnostics CRP is often used to distinguish between viral and bacterial infections, as the amount of CRP increase is notably higher in bacterial infections. Often CRP is also determined to check for the success of a therapy, e.g. an antibiotic therapy.
A Marker for IBD
CRP also supplements calprotectin as a reliable marker for the clinical course of inflammatory bowel disease (IBD), helping to predict relapses at the onset. The combination of the two markers has shown to increase the specificity for detecting inflammation in
Crohn’s disease.
DIAQUICK Assay
The CRP DIAQUICK Test Cassette immunochromatographic lateral flow assay provides semi-quantitative detection of C-Reactive Protein in whole blood, serum or plasma, manufactured by Dialab.
Read results within 5 minutes
3 indicator lines to quantify the presence of CRP
Detection levels: ≥ 10 mg/L, ≥ 40 mg/L and ≥ 80 mg/L
Faecal Occult Blood Testing
Qualitative faecal immunochemical tests (FIT) can be as easy as traditional guaiac methods for near patient testing or when the requirement for a fast turnaround impedes the use of a quantitative FIT service.
No Dietary Assay Interference
It is common for guaiac-based methods to recommend adherence to a special diet in the days prior to testing. This is to avoid interference from peroxidases or animal haemoglobin, but is a distinct draw back when you need to test in an acute setting. There are no dietary restrictions when using the DIAQUICK FOB lateral flow assays, as these use antibodies that specifically bind human haemoglobin (Hb), with a sensitivity of 5µg Hb/g faeces.
The DIAQUICK FOB cassette offers the specificity of a FIT in a simple yes/no manual test format:
Specific, Sensitive, Simple
Easy to perform
Result in 5 minutes
Specific for human Hb
Sensitivity 5µg Hb/g faeces
No dietary preparation required
Infectious Diseases
Infectious diseases are transmissible or communicable illnesses and can spread quickly in some areas and become epidemics. It is critical to quickly diagnose initial bacterial, fungal or viral infections through in vitro diagnosis to prevent further spread . The LFA is the most popular diagnostic tool that meets the required standards for rapidly detecting the presence or absence of suspected infection.
Available assays include:
H. pylori, a common type of bacteria that can lead to peptic ulcers and gastritis
Cryptococcus species, one of the most common HIV-related opportunistic infections
Aspergillus fungi commonly found in soil and dust that if inhaled can cause deadly infection in the immunocompromised
Viruses such as Infectious Mononucleosis
Pregnancy Testing
POCT for the detection of pregnancy and the prediction of ovulation has grown and evolved since the introduction of the first qualitative pregnancy test marketed directly to the consumer over four decades ago.
Available assays include:
Human chorionic gonadotropin (hCG) is a glycoprotein hormone secreted by the developing placenta shortly after fertilisation.
In normal pregnancy, hCG can be detected
in serum, plasma and urine as early as 7 to 10 days
after conception.
The DIAQUICK hCG Combo Cassette produced by Dialab is for use with urine, serum or plasma samples.
For more advice on products that can help support your Point of Care applications.
