Using the SureScreen CRP tests
The SureScreen CRP test is a semi-quantitative test for detection of CRP.
The test result is available in 5 minutes.
How to use the test:
- Draw a blood sample from a finger prick into a capillary tube.
- Add the blood from the capillary tube to the dilution tube with buffer. Bottom up and down the tube several times to mix the specimen well.
- Place the cassette on a clean and level surface. Add 3 drops of diluted specimen and start the timer. Wait for the coloured line(s) to appear.
- The result is available and should be read at 5 minutes (and no longer than 8 min).
Download a SureScreen package insert or read about the test on the SureScreen Diagnostics website.
How to interpret the results:
A recent independent validation of the SureScreen CRP tests found that:
- For samples with low CRP levels (under 10), the test does have good sensitivity and specificity.
- For samples with high CRP levels (over 80), the test does not have good sensitivity and specificity.
As such, we recommend using the test to "rule out” probable benefit from antibiotic treatment.
If a test shows only the control line, then clinicians can be confident that the CRP level is below 10 and, if the patient has been unwell for over 24 hours, then the patient is unlikely to benefit meaningfully from antibiotics.
If a test shows one or more of the T1, T2 or T3 lines, then clinicians can be confident that the CRP level is 10 or above and, based on clinical assessment, antibiotics or a back-up/delayed antibiotic prescription may be needed.
The line next to the letter C is a control line; if the control line does not appear, the test is invalid.
| Control line appears but no line appears in T region | There is either no CRP in the sample or the CRP is below 10 mg/l |
Antibiotics are unlikely to be beneficial |
| Any one or combination of test lines (T1, T2 and T3) appear | CRP is 10 mg/l or higher |
Based on your clinical assessment: antibiotics may be needed or a back-up/delayed antibiotic prescription may be helpful |
Download a printable summary sheet for interpreting CRP test results (pdf).
Practicalities:
- Store in a dry place at room temperature or refrigerated (2-30⁰C).
- The cassette is stable through to the expiration date printed on the sealed pouch.
- The cassette must remain in the sealed pouch until use.
- Use a lancet and capillary tube to collect blood sample.
- Dispose the cassette in a medical waste bin.
- There is no quality control checks required for this test.
Support:
Contact details for the SureScreen Diagnostics are available online.
If you wish to order more SureScreen CRP tests as part of the STEP-UP research study, email the study team.
Performance:
The SureScreen package insert has information about performance characteristics of the SureScreen CRP tests (compared to another commercial CRP test) and within-device precision. The results of a recent independent validation have been fed back to the manufacturer and are currently being considered. In the meantime, advice on interpretation of CRP test results have been updated on this website [28/11/2019] and practices in the STEP-UP IMPLEMENT study have also been informed [28/11/2019].
