Homocysteine (for homocystinuria)
Diagnosis of homocystinuria. Plasma levels are used in
preference to urine measurements as the latter may only be
increased when the plasma protein binding capacity has been
exceeded, thus giving rise to false negative results.
Request on ICE
Analysed by referral laboratory if specific criteria met.
Agreed with Consultant Biochemist.
Plasma - green-top heparin tube
1 mL minimum
Sample must be transported to laboratory and separated within 1
hour of collection.
Patients must be bled at Southend Hospital
Sent to referral lab (Addenbrookes, Cambridge)
Causes for Rejection
Unlabelled or incorrectly labelled sample; delay in transit to
Males: <18 umol/L
Females: <16 umol/L