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PTD - 247

Test Directory - Homocysteine

Clinical Indications

Possible homocystinuria
Premature cardiovascular disease
Thrombotic tendency
Possible B12/folate deficiency

Request Form

Combined Pathology Blood form (Yellow/Black)


Referred test: Analysed by Medical Biochemistry, University Hospital, Wales if specific criteria met.

Specific Criteria

Agreed with Consultant Biochemist.

Patient Preparation

Patient should be fasting as homocysteine levels may increase after food.



Sample must be transported to laboratory and separated within 30 minutes of collection. Patients must be bled at Basildon Hospital.

Turnaround Time

3 weeks


EDTA Plasma


2 ml


Pink top (EDTA) tube

Causes for Rejection

Unlabelled sample. Delay in transit to laboratory.

Reference Range

Approximately less than 16 mmol/l 


Raised levels may indicate a genetic disorder or sulphur amino acid metabolism and/or B12/folate deficiency.

Raised levels are reported to be a risk factor for premature cardiovascular disease and/or clotting tendency.

Lab. Handling

Processing: Centrifuge sample within 30 minutes of collection and store at 4C in the separating fridge. If there will be a delay in sending the sample to the referral laboratory it should be frozen at -20C in separating freezer (CB40), active frozen rack 110.
HCYS and send or BPRO and save in separating freezer (CB40) at -20C, saved frozen rack.

Version 1.0 / May 2014                                                                                                           Approved by: Consultant Biochemist