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Toxoplasma Reference Unit



Contact Us

Public Health Wales Microbiology Swansea
Singleton Hospital

Public Health Wales Microbiology Swansea
DX 6070300
Swansea 90 SA

Laboratory opening hours: 08:45-17:00 (Monday to Friday)
Results and general enquiries: 01792 285058


Consultant Clinical Scientist and Head of Unit – Professor Edward Guy​

Deputy Head of Unit – Dr Stephen Hadfield​

Operational Manager, Serodiagnostic Services – Heather Alderson​


Core Services

  • Laboratory Investigation of Toxoplasma Infection ​

    Immunocompetent patients (Referred specimens)​
    Confirmatory testing is offered where this will result in more timely and appropriate patient management through exclusion of other aetiologies.​

    Vulnerable clinical groups (Reference specimens)​
    Specialist testing is offered in a range of clinical scenarios including pregnancy/infants, HIV/AIDS, Organ Transplantation/other immunosuppressed, suspected ocular disease in order to both achieve a definitive diagnosis and facilitate timely and appropriate patient management.​

  • Clinical advice​
    Specific management strategies based on results of Reference tests or general advice, including further investigation, anti-toxoplasma therapies and other management options. ​

  • Public Health advice on risk and risk-reduction​
    Both general information and information on an individual case basis can be provided​



  • Reference serology test -IgG & IgM (Sabin-Feldman Dye Test - DT)
  • IgM EIA
  • IgM/IgA Immunosorbent Agglutination Assay (ISAGA)
  • IgG Avidity
  • Molecular Diagnosis (PCR)

Clinical Scenario

Helpful Specimens


  • Acute toxoplasmosis
  •  Blood (clotted or serum)
  • DT and IgM EIA
Congenital Toxoplasmosis
  • Mother
  • Blood (clotted or serum) 
  • DT and IgM EIA, other assays as required 
  • Amniotic fluid (>1ml)
  • PCR 
  • Neonate/infant 
  • Neonatal blood (clotted/serum)
  • EDTA blood 
  • PCR
  • Stillbirth
  • Foetal blood (clotted/serum)
  • Foetal CNS/cardiac tissues/EDTA blood 
  • PCR
  • Blood (clotted or serum) 
  • DT and IgM EIA, IASGA-M
  • CSF (if CNS involvement)/EDTA blood
  • PCR
  • CNS tissue
  • PCR
Organ Transplant
  • Pre-transplant donor and recipient screen
  • Blood (clotted or serum) 
  • DT and IgM EIA
  • CSF (if CNS involvement)/EDTA blood
  • PCR
  • Post-transplant
  • Blood (clotted or serum)
  • DT and IgM EIA
  • EDTA blood
  • PCR
  • CNS tissue
  • PCR
Ocular Toxoplasmosis


  • Blood (clotted or serum)
  • DT and IgM EIA
  • Aqueous/vitreous fluid
  • PCR



Reference specimens (free of charge)

All reference testing is carried out free of charge for all National Health Service laboratories in England and Wales.

Reference specimens are:

Dye Test/IgM  - All immunosuppressed/immunodeficient patients (e.g. HIV/AIDS, tissue transplant recipients, cancer therapy recipients/patients) and neonates.

PCR – EDTA blood requested by TRU, and any other appropriate specimen-types (CSF, ocular fluids, BALs, amniotic fluid, products of conception)

Referred specimens (charged)

Referred serum samples from NHS laboratories will be subject to charge; prices are reviewed annually and available on request.

Referred specimens are:

Dye Test/IgM EIA – Serum/plasma (immunocompetent patients)

PCR - EDTA blood where PCR was not requested by TRU (unless indicated to be IgM-positive by referring laboratory)

Non-NHS specimens (charged)

Samples received from Private Laboratories and from outside the UK will be subject to charge; prices are reviewed annually and available on request 

Sample Transportation

Samples submitted to the Toxoplasma Reference Laboratory should be packaged in accordance with current UK or International postal regulations and sent either by Royal Mail, DX or other Courier Services. 

Specimen Submission

Specimens must be correctly labelled and request forms adequately completed to ensure that the appropriate investigations are carried out and findings reported back to sending laboratories with minimum delay.

Most samples sent to the reference laboratory will have been tested prior to referral. All Toxoplasma test results and other relevant findings obtained prior to referral will be helpful in clinical interpretation of Reference Unit results and should, therefore, be included when samples are submitted for reference testing. The volumes listed below are the preferred minimum volumes.​

Toxoplasma DNA detection by PCR

TRU uses a real-time PCR assay to detect Toxoplasma DNA.

Samples and minimum volumes to send for Toxoplasma PCR are:

  • EDTA whole (unseparated) blood samples (2.5-5ml), (neonates 0.5-1ml)
  • CSF Samples - 300µl
  • Vitreous Fluid - 300µl
  • Amniotic Fluid >1ml
  • DNA Extracts –Telephone to discuss

Samples sent for detection of Toxoplasma should NOT be centrifuged prior to sending. Centrifugation can remove toxoplasma cells from the supernatant and result in false-negative findings.

Samples should be stored at 2-8oC prior to transport

Toxoplasma Serology

A minimum volume of 1ml serum is preferred. (neonates 200µl).

Samples should be stored at 2-8oC prior to transport.

If insufficient volume is available and a repeat sample cannot be obtained, please phone the laboratory to discuss. 

Completion of Request Form

Minimum information required is:

  • Full Name of Patient or Patient Identity number               
  • Date of birth
  • Sex
  • Sending Laboratory’s Reference Number
  • Date sample was collected
  • Tests or investigations required
  • Laboratory Findings
  • Address of requester (including postcode)
  • Telephone number
  • Relevant clinical details
  • Date of onset and duration of illness

Other helpful information (If relevant)

  • Travel history
  • Occupation/pets/animal contact

Urgent Samples

The reference laboratory will endeavour to process samples urgently in acute or severe cases where findings will inform clinical management decisions. Urgent samples are usually received during normal working hours. Please telephone to inform the laboratory of urgent requests prior to despatch. Mark “urgent” clearly on the request form.

Where urgent samples are sent by courier outside normal working hours, arrangements must be agreed with the laboratory before the sample is sent.  

Turnaround Times

The TRU aims to complete testing within the times indicated below. Results are returned by Royal Mail to the address on the request form, but can be telephoned where request form indicates these are required urgently.

Turnaround Times (from time of receipt of sample to issue of report)

Primary reference serology (Dye Test & IgM EIA)        

within 7 working days

Primary reference serology


Additional serology testing

(IgG avidity assay, ISAGA IgM/IgA)       

within 10 working days

PCR (Molecular Diagnostics)     

(N.B emergency PCR 1 day, where clinically indicated and agreed in advance with the reference unit) 

3-10 working days