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Test Category: Biochemistry

Investigation Name:Porphyrins

Intro:

***IMPORTANT ***
PLEASE READ the following before sending samples; the testing strategy and the options available on the electronic requesting systems are dependent upon clinical signs and symptoms.
CLINICAL DETAILS MUST BE PROVIDED. Include symptoms, relevant family history, and type of porphyria suspected, in order to guide appropriate testing. Note that samples are sent to the Cardiff Porphyria Service, and testing is not routinely available out of hours and over the weekend. For urgent clinical advice please contact the National Acute Porphyria Service (in hours 029 21846588 and out of hours 029 20747747).
Electronic requesting options:
1) ?Acute symptomatic porphyria
Current symptoms including: acute abdominal pain, vomiting, neurological, convulsions, hyponatraemia, psychiatric Sample: Random urine (plain white top), preferably early morning and EDTA whole blood (purple top). PROTECT FROM LIGHT
2) ? Acute asymptomatic porphyria
Currently asymptomatic but previous symptoms including: acute abdominal pain, vomiting, neurological, convulsions, hyponatraemia, psychiatric or asymptomatic with a positive family history. Sample: Random urine (plain white top), preferably early morning; EDTA whole blood (purple top) and faecal sample (blue top) PROTECT FROM LIGHT.
Biochemical tests for porphyria may return normal results in non-active porphyria. Please contact the National Acute Porphyria Service for further advice if required.
3) ?Cutaneous (bullous) porphyria
Symptoms: Skin fragility, blisters, milia, painful photosensitivity Sample: Random urine (plain white top) and EDTA whole blood (purple top).Faecal porphyrin analyses may be required following initial analysis. PROTECT FROM LIGHT
4) ? Acute photosensitive porphyria
Symptoms: Extreme sensitivity to sunlight, intense pain and burning within minutes of exposure. Sample: EDTA whole blood (purple top). PROTECT FROM LIGHT
5) Porphyria monitoring
Sample for known acute intermittent porphyria, variegate porphyria, hereditary coproporphyria or porphyria cutanea tarda: Random urine (plain white top), preferably early morning. PROTECT FROM LIGHT
Sample for known erythropoietic protoporphyria: EDTA whole blood (purple top). PROTECT FROM LIGHT.
Uncertain clinical presentation:
Please discuss with Duty Biochemist.

Pathology Laboratory:Clinical Chemistry/ Biochemistry

Requestable Seperately?No

Part of Profile:Yes

Tests in Profile:Dependent upon clinical details: Urine porphobilinogen (PBG), Urine PBG/Creatinine ratio, Total Urine Porphyrin, Urine Porphyrin/Creatinine ratio, Plasma Porphyrins, Faecal Porphyrins

Minimum Sample Volume:3 mL urine, 2 mL EDTA, 2 g faeces

Expected Turnaround Time:Routine: 7-14 days; Urgent: ~2 days (by prior arrangement with the Duty Biochemist)

Test Code:Acute photosensitive porphyria (APP), Acute porphyria screen (APS), Cutaneous bullous porphyria screen (CBPS), Acute asymptomatic porphyria screen (AAPS), Monitoring known acute porphyria (MKAP).

Sample Type:

See testing strategy in ‘Information’ section. Urine (plain), EDTA Blood (purple top), Faeces (blue top)

Complex Reference Range:Urine PBG/Cre <1.5 umol/mmol
Urine porphyrin/Cre <35 nmol/mmol
If patient <16 years profile includes ALA/Cre <5.2umol/mmol
If PBG/Cre or porpyrin/Cre is raised urine and EDTA blood is referred for analysis.

Collection Conditions / Other Information:PROTECT SAMPLES FROM LIGHT. All samples must be protected from light immediately after collection by wrapping in foil or placing in a brown envelope.
LAB INFORMATION: If sample arrives unprotected from light but was collected <6hrs ago, protect from light, add comment in winpath and write ‘exposure to light (<6hrs) has occurred’ on request form sent to Cardiff.
If sample arrives unprotected from light and was collected >6hrs ago, sample cannot be analysed – reject samples and request repeat. Please pass on to BMS immediately.

Reference Laboratory Details:Dept of Medical Biochemistry, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW. (Tel: 029 2074 3565)

Referred to Another Laboratory?Yes

Storage Requirements:Store at 4 °C prior to posting. Do not freeze or centrifuge.
Post first class, protected from light. Avoid posting on a Friday.

Contact Number: Duty Biochemist – 01902 695290, 01902 307999 ext. 85290