Cystine (Leucocyte)
(referred to external laboratory)
Department of Newborn Screening & Biochemical Genetics, Birmingham Children's Hospital
Add-on requests: NA
Minimum Retest Interval: NA
Collect the blood sample using normal venepuncture technique into a lithium heparin tube (green-top). Please note: at least 10 mL Lithium Heparin blood is required for testing.
It is essential to contact the Duty Biochemist at least 48 hours before sample collection. Transport arrangements to the referral laboratory must be organised in advance due to the limited stability of this analyte.
Samples should be sent to the laboratory on the same day as collection to ensure sample integrity is maintained. If a delay in receipt of the sample is anticipated, please contact the laboratory to discuss storage requirements.
To ensure samples arrive at the referral laboratory by 1:00 pm on the day of collection, they must be delivered to us early in the morning. Please do not take bloods on a Friday, as samples cannot be stored onsite.
For generic information on test requesting, sample labelling and packaging, and sample transport – see the frequently asked questions here.
Adult sample type:
Paediatric sample type:
Lithium-Heparin whole-blood
Based on receipt at testing site.
Within 6 weeks
Please access the referral laboratory website/laboratory handbook for information on reference ranges. Where required, reference ranges and/or interpretative comments provided by the external referral laboratory may be added to reports alongside results.
Results outside the reference range do not necessarily indicate disease. Similarly, results within the reference range do not preclude abnormality. Please contact the Duty Biochemist for discussion of individual patient results.
Monitoring and diagnosis of cystinosis, a rare autosomal recessive lysosomal storage disease.
Note, cystinosis is NOT the same as cystinuria (a cause of renal stones). Please ensure that the correct test is being requested.
Factors that significantly affect result
There are a number of non-pathological factors that can influence levels of specific analytes, giving falsely elevated or reduced levels. If you require more information regarding the effects of these factors on the individual test results, please contact the Duty Biochemist.
For tests performed at an external referral laboratory, consider contacting the performing laboratory directly for specialist advice on the interpretation of results.
Please provide relevant clinical details, including whether the test is for diagnosis or monitoring.
Please note that Cystinosis is NOT the same disease as cystinuria (a cause of renal stones). Please ensure that the correct test is being requested.
Reviewed / Updated On: 02/12/2025
