Test ID: FIL
Filaria, Blood
NY State Approved 
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Detection of the microfilariae of the lymphatic filariases (not onchocerciasis) in the peripheral blood by stained smears and/or a concentration technique
Method Name A short description of the method used to perform the test
Fresh and Concentrated, Microscopic Examination
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube: Light-blue top (sodium citrate)
Specimen Volume: 4.5 mL
Collection Instructions: Certain of the microfilariae have a nocturnal periodicity, and the blood specimen is best taken at night between 10 p.m. and 2 a.m.
Forms: If not ordering electronically, submit a Microbiology Request Form (Supply T244) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood Na Cit | Ambient (preferred) | 72 hours |
| Refrigerated | 72 hours |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Filaria are nematodes (roundworms) which are widespread in nature, especially in tropical areas. The adults produce microscopic microfilariae which can be transmitted to humans by biting insects (mosquitos or blackflies).
In the lymphatic filariases, the microfilariae migrate to the lymphatics where they mature to adults and cause obstruction (elephantiasis).
Lymphatic filariases caused by Wuchereria bancroftii occurs primarily in Africa and that caused by Brugia malayi occurs in South and East Asia. Treatment with diethylcarbamazine or ivermectin is effective in all but the most advanced stages.
In onchocerciasis, adults mature in subcutaneous nodules and release new microfilariae which may migrate to the eye and cause blindness (African River Blindness). Ivermectin use has dramatically improved the outlook for control and treatment of onchocerciasis in Africa.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Negative
If positive, organism is identified.
Interpretation Provides information to assist in interpretation of the test results
Positive results are provided with the genus and species of the microfilariae, if identifiable.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Onchocerciasis cannot be diagnosed using blood (a "skin-snip" examination is necessary).
Microfilariae may be seen in malaria or differential count peripheral blood smears, but concentration techniques are more efficient.
Certain of the microfilariae have a nocturnal periodicity, and the blood specimen is best drawn at night, between 10 p.m. and 2 a.m.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Grove DI: Tissue nematodes (trichinosis, dracunculiasis, filariasis). In Principles and Practice of Infectious Diseases, 4th edition. Edited by GL Mandell, RG Douglas Jr, JE Bennett. New York, Churchill Livingstone, 1995, pp 2531-2537
Method Description Describes how the test is performed and provides a method-specific reference
Unstained whole blood is first examined microscopically in search of motile microfilariae. Portions of the specimen are concentrated by centrifugation after adding 2% formalin. The sediment is examined as a wet preparation, and, if positive, the slide is air dried, fixed in methyl alcohol, and stained with Giemsa to aid in species identification. (Garcia L, Bruckner D: Diagnostic Medical Parasitology. 3rd edition. Washington, DC, American Society for Microbiology, 1997)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; 3 p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
87207
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| FIL | Filaria, B | In Process |
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