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PTD-279

Test Directory - Porphyria Studies

Synonyms

Porphrins, Porphobilinogen, PBG, 

Clinical Indications

Clinical Presentation

Specimens

Comments

Acute neurological attacks (suspected AIP, VP, HCP)

Urine
Faeces
Blood

To exclude a current attack urine alone is adequate.

Acute photosensitivity (suspected EPP)

Blood

Urine and faeces of no value.

Skin lesions (suspected PCT, VP, HCP or CEP)

Urine
Faeces
Blood

To monitor patients with PCT send early morning spot urine only in white top universal, protected from light.

Request Form

Combined Pathology Blood form (Yellow/Black)

Availability

Referred Test: Analysed at the Clinical Biochemistry Department, Bedford Hospital, if specific criteria met. All requests will be vetted by Consultant Biochemist to ensure correct samples based on clinical details are referred.

Specific Criteria

Investigation of suspected porphyria. The incidence of porphyria is such that an average District should contain about 20 patients with overt porphyria. The rate of diagnosis is much less than this and may be due to failure to suspect porphyria as a possible diagnosis.

Turnaround Time

The routine turnaround time is 1-2 weeks but urgent requests can be arranged with prior discussion with the Consultant Biochemist at Basildon Hospital.

Specimen

Early Morning Urine and/or Faeces (small random sample approx.10g) Blood (plasma and red cells).

All samples must be protected from light

Volume

2 ml (blood); 10 ml (urine); 10 g (faeces)

Container

Pink/purple top (EDTA) tube. Green top (lithium-heparin) also acceptable.

Urine and faeces should be collected into plain sterile containers.

All samples must be protected from light immediately after collection

Causes for Rejection

Unlabelled sample.

Interpretation

Acute neurological attacks: if urine screen normal and urine was collected during a suspected attack then no further tests are normally required.

A interpretive comment will be added to reports.

Lab. Handling

Processing:

Urine and/or Faeces must be stored at -20C in the separating freezer (CB40) until sent to the referral laboratory.

The blood sample must be centrifuged and the plasma separated from the red cells; both the plasma and red cells must be stored at 4C in separating fridge (CB39).

Referral: UPOR (urine porphyrin and PBG only) / SPOR (full porphyrin screen including faeces and blood) and send to the referral laboratory or BPRO and save at -20C in separating freezer (CB40)  

Urgent analysis can be arranged with prior approval from the Biochemist.

All samples must be protected from light prior to analysis/referral.

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 Version 1.1 / June 2015                                                                                                         Approved by: Consultant Biochemist