Sickle screening test
The sickle cell test is available as part of haemoglobinopathy screening. Hb S is an abnormal haemoglobin caused by a single point substitution of valine for glutamic acid in position 6 of the β-globin chain. The homozygous state, sickle cell anaemia, is characterised by the formation of sickle red cells and moderate to severe anaemia. Sickle cell trait, the heterozygous state, is very common, with no associated haematological abnormalities. In vivo sickling occurs only at very high altitudes and at low oxygen pressures. The sickle solubility screen provides a quick and reliable method of detecting this abnormal haemoglobin. The test is based on the principle that Hb S, in its reduced state, is less soluble in concentrated phosphate buffers than nearly all other haemoglobins (the exceptions being the rare Hb C Harlem and Hb C Georgetown). A sickle screen is required for patients in high risk groups, especially prior to a general anaesthetic and if there is no prior haemoglobin electrophoresis result with imminent surgery expected. If surgery is planned for more than one week away, haemoglobin electrophoresis results should be performed instead of a sickle screen.
Please note: unlike the haemoglobin electrophoresis, the sickle screen test does not differentiate between the sickle cell trait and the sickle cell anaemia state (or variants of this). All samples with requests for sickle screening tests will be followed up with haemoglobin electrophoresis and additional haemoglobin studies if deemed appropriate.
Sickle screens are performed prior to emergency surgery or where full haemoglobinopathy testing will not be available prior to anaesthesia.
The laboratory is not UKAS accredited for this test.
This test is not currently accredited
Record last updated
August 27, 2025
Sample Container
4ml EDTA Vacutainers (Lavender top)
Sample Container
K2EDTA Paediatric Tube (Lavender top)
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Test Results
Yes, we have a Pathology User Guide
Yes. Please email your request to Imperial.nwlpcustomerservice@nhs.net
Results are communicated to clinical staff and are normally not communicated direct to patients either on telephone requests or in written report. If you need to contact us please click here to view the contact details page
Please contact the Customer Service Team Monday to Friday from 8:30am – 6:00pm on 0203 313 5353. Alternatively, see the Pathology User Guide for how to contact the relevant department. If advice is not urgent you can also email your query to Imperial.nwlpcustomerservice@nhs.net
Additional tests may be added by discussion with the relevant laboratory. The time limit for adding additional tests to a sample already received in the laboratory will depend on the type of sample and the department it was sent to.
Information on the repertoire of tests performed by pathology, including reference ranges, turnaround times and specimen requirements, can be found in the test directory.
Phlebotomy services are not managed by NWLP. For further information please see:
Imperial College Healthcare Trust Phlebotomy services
Chelsea and Westminster Hospital NHS Foundation Trust Phlebotomy services
NWLP operates UKAS accredited medical laboratories as per the references below. The current scope of accreditation for all NWLP’s laboratories can be found on the UKAS website.
See the following UKAS ref numbers:
- Clinical Biochemistry Ref: 8673
- Haematology and Blood Transfusion Ref: 8674
- Infection & Immunity Sciences (Including Immunology, Virology, Microbiology and Histocompatibility and Immunogenetics ) Ref: 8659
- Cellular Pathology (Including Histopathology, Cytology and Molecular Pathology) Ref: 9615
If you require copies of our certificate of accreditation and associated documentation please contact Imperial.nwlpcustomerservice@nhs.net.
UKAS requires the laboratories to be accredited for a particular repertoire/scope (ISO15189), any changes or additions to repertoire require assessment by UKAS (extension to scope).
The BD Hospital Tube Guide, BD GP Tube Guide and BD Paediatric Tube Guide provide visual references to the correct tube types and collection instructions.
Home testing
INSTRUCTION SHEET FOR BLOOD SAMPLE COLLECTION
We also have two instruction videos available (one with subtitles and one without) – please click on the links to view the videos on Google.
Our accreditations
Upholding excellence in diagnostic standards
Our laboratories are accredited by the UK Accreditation Service (UKAS) against the international standard ISO15189:2022. UKAS is the accreditation body for the UK that assesses medical laboratories.
Find out more about our accreditations on the UKAS website.
UKAS website