Module 9 - Concentration Techniques

CONCENTRATION TECHNIQUE

Separate protozoan cysts and helminth eggs

Specific Gravity

PRINCIPLE OF CONCENTRATION TECHNIQUE:

CONCENTRATION TECHNIQUE

Recommended in cases of light infections

Fresh or Preserved Stool Specimens

CONCENTRATION TECHNIQUE Can be performed on

• Sedimentation

• Flotation

TYPES OF CONCENTRATION TECHNIQUE

SINK

A parasite that has a higher specific gravity than the reagent will

FLOAT

a lower specific gravity will

SEDIMENTATION

Recommended for general diagnostic laboratories because they are easier to perform and less prone to technical errors

• Formalin – Ether/Ethyl Acetate Concentration Technique (FECT)

• Acid Ether/Ethyl Acetate Concentration Technique (AECT)

• Merthiolate Iodine Formaldehyde Concentration Technique (MIFT)

SEDIMENTATION PROCEDURES:

FORMALIN ETHER/ETHYL ACETATE CONCENTRATION TECHNIQUE (FECT)

Useful in the recovery of both helminth eggs and protozoan cyst

FORMALIN ETHER/ETHYL ACETATE CONCENTRATION TECHNIQUE (FECT)

Preparation contains more fecal debris than a flotation technique (advantage)

• 10% Formalin

• Ether

FORMALIN ETHER/ETHYL ACETATE CONCENTRATION TECHNIQUE (FECT)

Main reagents used are:

FORMALIN ETHER/ETHYL ACETATE CONCENTRATION TECHNIQUE (FECT)

Used as screening test for food handlers and Overseas Filipino Workers (OFWs)

ACID ETHER/ETHYL ACETATE CONCENTRATION TECHNIQUE (AECT)

Recommended for the recovery of Trichuris, Capillaria, and trematode eggs, especially Schistosoma.

ACID ETHER/ETHYL ACETATE CONCENTRATION TECHNIQUE (AECT)

Also the choice if stool material comes from animals like cats and dogs

• 40% Hydrochloric acid (HCl)

• Ether

ACID ETHER/ETHYL ACETATE CONCENTRATION TECHNIQUE (AECT)

Main reagents used are:

MERTHIOLATE IODINE FORMALDEHYDE CONCENTRATION TECHNIQUE (MIFT)

this technique is widely used in the Schistosomiasis Control and Research Project in the Philippines

MERTHIOLATE IODINE FORMALDEHYDE CONCENTRATION TECHNIQUE (MIFT)

Found to be efficient in the qualitative diagnosis of schistosomiasis.

MERTHIOLATE IODINE FORMALDEHYDE CONCENTRATION TECHNIQUE (MIFT)

Useful for the fixation of intestinal protozoans, helminth eggs, and larvae.

• Merthiolate

• Iodine

• Formalin

• 0.6 mL Ether

MERTHIOLATE IODINE FORMALDEHYDE CONCENTRATION TECHNIQUE (MIFT)

Main reagents used are:

• Brine Flotation Technique

• Sheather’s Sugar Flotation Technique

• Zinc Sulfate Flotation

FLOTATION PROCEDURES:

BRINE FLOTATION TECHNIQUE

Makes use of a saturated table salt solution or sodium chloride

BRINE FLOTATION TECHNIQUE

Stools are directly mixed with the brine solution • No need for centrifugation since helminth eggs rise to the surface

BRINE FLOTATION TECHNIQUE

Low – cost but helminth eggs like hookworm and Schistosoma become badly shrunken

BRINE FLOTATION TECHNIQUE

Not useful for operculated eggs like Clonorchis, Opistorchis, and heterophyids

Boiled Sugar Solution preserved in phenol

SHEATHER’S SUGAR FLOTATION TECHNIQUE

Reagent:

Coccidian oocyst

SHEATHER’S SUGAR FLOTATION TECHNIQUE

Parasites recovered:

33% zinc sulfate solution

ZINC SULFATE FLOTATION TECHNIQUE

Reagent:

1:18-1:20

ZINC SULFATE FLOTATION TECHNIQUE

Specific gravity: