Diagnostic Parasitology Laboratory

The Diagnostic Parasitology laboratory is located in the Department  of Clinical Services and offers a referral service for the identification of human parasites from clinical specimens.

The laboratory accepts samples from NHS and private hospitals, and private laboratories.
A charge is made for all laboratory services, for current prices please telephone laboratory staff on 0151 705 3220

Please note that the Laboratory is open for receipt of specimens 8:00 - 13:00 & 13:30 - 16:00 Monday to Friday

The laboratory is closed at weekends and on Bank Holidays

Samples should be sent by first class mail, or courier to:

The Clinical Diagnostic Parasitology Laboratory
Liverpool School of Tropical Medicine
Pembroke Place
Liverpool
L3 5QA

OR

If in the Hays DX scheme:
Liverpool School of Tropical Medicine
Diagnostic Laboratory
DX 6966301
Liverpool 92L

In order to comply with specimen acceptance policy , samples sent to the laboratory for diagnosis (and accompanying forms) must be labelled with a minimum of 3 out of the 6 of our sample identification criteria:

1. Family name (or number)
2. First name(s)
3. Date of Birth
4. Laboratory reference number
5. Hospital number
6. Specimen date

Unfortunately specimens not stating at least 3 of these criteria will be rejected.

IT IS IMPORTANT THAT CLINICAL DETAILS AND TRAVEL HISTORY OF THE PATIENT ARE INCLUDED PLUS FULL ADDRESS/TELEPHONE NUMBER FOR RETURN OF RESULTS

TURN AROUND TIME FOR RESULTS

For technical advice regarding samples/tests and for interpretation of results please contact Dr W.Bailey at the Diagnostic Laboratory 0151 705 3220/3290

For clinical advice and for the treatment of parasitic diseases please contact one of the consultant physicians at the Tropical School.

DIAGNOSTIC TESTS

MICROSCOPY FOR BLOOD PARASITES

Malaria

Samples are screened using thick blood films, thin films are examined on positive samples. If P.falciparum is found, parasitaemia is performed. Rapid diagnostic tests (RDT’s) are available.

Sample requirements: Original (EDTA) blood sample plus 2 unstained thick films & 2 unstained, methanol fixed, thin films.

We would be grateful if you would complete the HPA Malaria reference Lab. report form and enclose with the sample. Sample date and patient travel history should be stated

Other blood/tissue parasites, please contact laboratory PRIOR to sending specimens.

African trypanosomiasis

Thick blood films and QBC concentration technique if films are negative.Trypanosomes may not survive in a blood sample for more than a few hours therefore blood films should be made as soon as possible following blood collection. Samples for QBC should be examined on the day of collection.  

Sample requirements, unstained thick/thin films, EDTA blood sample                      

If a CSF sample is to be examined for trypanosomes it should be examined within 20 minutes of L.P.    

Filariasis

A wet preparation is examined, negative samples are filtered using a 3.0µm Nuclepore membrane. If  W.bancrofti is suspected  blood collection time should be between 22.00 and 02.00 hours.

Sample requirements: EDTA blood

Leishmaniasis: It is important that travel history is stated.

Sample requirements:

Cutaneous Leishmaniasis

Visceral leishmaniasis

FAECAL PARASITES

A concentration technique is routinely performed on all faecal samples for the presence of  cysts, ova and larvae. Direct microscopy smears are examined where trophozoite stages of protozoan parasites are suspected.

Sample requirements: Minimum of ¼ specimen pot of faecal sample (10g)

NB If Entamoeba histolytica trophozoites are suspected a “hot” stool must be examined (specimen must reach the laboratory within 30 minutes of sample being produced).

Other, non-routine/special faecal tests

Cryptosporidia

Z-N technique is used on slides from formol-ether deposit for identification of oocysts.

Dientamoeba fragilis

Romanowsky stained smears for the  identification of D.fragilis. trophozoites.

Sample requirements: please send a fresh (dated) unfixed sample of faeces plus a thin faecal smear -made without saline and fixed once dry for 1 minute in methanol.

Enterobius vermicularis

The rectal swab method is used – a damp, cotton bud is wiped around the peri-anal area and then returned to the bottle of physiological saline. This bottle is sent to the laboratory for examination.


Enterocytozoon bieneusi (microsporidia)

The laboratory offers the Calcofluor method as a screening test for microsporidial spores. Faecal samples must be mixed with 10% formol saline immediately following defaecation. Sample requirement: formed stool-approx 1g mixed in 2ml 10% formol saline, unformed sample- equal volumes of faecal sample and formol saline..


Strongyloides/Hookworm faecal culture

Faeces are cultured for filariform larvae using the charcoal technique.

Sample requirements: At least 100g  (half pot) of faeces. Samples should NOT be stored in a refrigerator following collection.   

Whole worms/proglottides

Whole worms for identification may be stored in 10% formol saline. Suspected Taenia species proglottides are best stored in physiological saline and sent to the laboratory as soon as possible (fixation may make subsequent identification difficult).

FAECAL ANTIGEN DETECTION TESTS

E.histolytica adhesin ELISA

To differentiate between cysts of E.histolytica/dispar as seen by faecal microscopy. Samples must not be bloody. The test must be performed on FRESH (< 24 hour old) NOT FIXED specimens OR samples which have been frozen and stored at -20°C within 24hours of defaecation.

Giardia lamblia (intestinalis) ELISA

If cysts cannot be identified by routine microscopy the copra ELISA is a sensitive method of diagnosis. Specimens should be fresh (< 24 hours old), or freshly-frozen at -20°C or mixed with 10% formol saline immediately within 24hrs of defaecation.. Fixed specimens may be stored at room temperature for up to 18 months.

Schistosoma haematobium

Urine is tested by dipstick for the presence of blood /Hb, and RBC’s. Urine is routinely filtered using 12.0µm polycarbonate filters. Sample requirement: total 10am – 2pm urine or terminal midday sample is ideally required.

Seminal fluid

Microscopy is performed for schistosome ova. Age of sample is not critical.

ANTIBODY DETECTION TESTS

Baseline titres quoted in our tests are from results on samples from UK residents not normally exposed to the test organism. Results on samples from patients  originating from areas endemic for parasites, and with low positive titres,  may be of little significance in their current illness .Interpretation of all results are subject to available clinical and travel information. A positive result may reflect previous infection.

Sample requirement: 5ml serum OR 10ml of clotted blood.