Parasitology Proficiency Testing Program
Parasitology PT Program
Parasitology PT Program
GENERAL CRITIQUE FOR 06 February 2006
The purpose of the New York State Proficiency Testing Program in the category of Parasitology General is to monitor the performance of applicant laboratories in detecting and identifying parasites in fecal emulsions, fecal smears, and blood films.
SAMPLE PREPARATION AND QUALITY CONTROL
All emulsions and slides used in this test were prepared by a commercial source. The emulsions were dispensed into the vials from pools which were continuously mixed during the loading process. Numerous samples of each test specimen were selected at random by the Parasitology Unit of the David Axelrod Institute for Public Health, and were checked to confirm their contents. Extensive quality control tests were also conducted by the supplying vendor and a detailed quality control report was submitted to the New York State Parasitology Laboratory for inspection and verification. Samples were authenticated by 80% of participating laboratories and/or referee laboratories.
GENERAL ANSWER KEY FOR 06 February 2006
| SAMPLE | CORRECT ANSWERS | POINTS |
|---|---|---|
| 06-K | Chilomastix mesnili | 20 |
| 06-L | Fasciola hepatica/Fasciolopsis buski | 20 |
| 06-M | Taenia sp. | 20 |
| 06-N | Blastocystis hominis | 20 |
| 06-O | Loa loa | 20 |
TOTAL POSSIBLE POINTS 100
SAMPLE 06-K Report Protozoa Only
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Chilomastix mesnili | 135/150 | 91 | 09/10 | Correct |
| NO PARASITES SEEN | 10 | 07 | 1 | Incorrect |
| Giardia lamblia | 03 | 02 | 0 | Incorrect |
| Blastocystis hominis | 01 | 0.6 | 0 | Incorrect |
| Cryptosporidium sp. | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Chilomastix mesnili was the correct response (91 and 90%). Quality control examination of 4% of this sample revealed cysts and trophozoites in almost every 40X field. Blastocystis hominis is also present but should not have been reported because "Protozoa Only" was requested. Other tests performed include Direct Immunofluorescent Assay and ELISA for Giardia lamblia and Cryptosporidium sp. which were negative for both organisms. A modified acid-fast stained smear was also negative.
DIAGNOSTIC CHARACTERISTICS
 |
Chilomastix mesnili has a worldwide distribution but is more common in warmer climates. It has both a cyst and trophozoite stage and is considered to be non-pathogenic. The cysts are lemon shaped and measure between 6-8 microns. They contain a single nucleus and a characteristic curved cytostomal fibril. The trophozoites are usually pear shaped and measure between 6-24 microns. They have a single nucleus and a cytostome located near the nucleus. The flagella can be difficult to see. Transmission occurs through the fecal oral route. |
SAMPLE 06-L Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Fasciola hepatica/Fasciolopsis buski | 133/148 | 90 | 10/10 | Correct |
| Paragonimus westermani | 09 | 06 | 0 | Incorrect |
| NO PARASITES SEEN | 04 | 03 | 0 | Incorrect |
| Diphyllobothrium latum | 02 | 01 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Fasciola hepatica/Fasciolopsis buski was the correct response (90 and 100%). Quality control examination of 4% of this sample showed an average of 15 ova per coverslip. Other tests performed include Direct Immunofluorescent Assay and ELISA for Giardia lamblia and Cryptosporidium sp. which were negative for both organisms. A modified acid-fast stained smear was also negative.
DIAGNOSTIC CHARACTERISTICS
 |
Fasciola hepatica is a liver trematode with a worldwide distribution. It is extremely rare in the United States. Humans become infected by eating uncooked aquatic plants containing metacercariae from the intermediate snail host. These metacercariae excyst in the duodenanum and migrate to the liver. Once the larvae enter the bile ducts they mature and begin to lay eggs which are the diagnostic stage. The eggs are very large measuring 130-150 microns by 60-90 microns. They are thin shelled and have an operculum. Although these eggs are similar in appearance to Paragonimus westermani they are easily distinguished by size. They are indistinguishable from Fasciolopsis buski. |
SAMPLE 06-M Report Helminths Only
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Taenia sp. | 149/149 | 100 | 10/10 | Correct |
| Hymenolepis nana | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Taenia sp. was the correct response (100 and 100%). Quality control examination of 4% of this sample revealed an average of 15 ova per coverslip. Also present are rareGiardia lamblia cysts. Other tests performed include Direct Immunofluorescent Assay and ELISA for Giardia lamblia and Cryptosporidium sp. which were negative for Cryptosporidium sp. but positive for Giardia lamblia. A modified acid-fast stained smear was also negative.
DIAGNOSTIC CHARACTERISTICS
 |
The diagnostic stage of the intestinal cestode Taenia sp. is the characteristic egg found in stool. These eggs are yellow-brown, round to oval and measure 35-40 microns. They have a thick radially striated shell and contain an oncosphere with visible hooks. Infection occurs when raw or poorly cooked beef or pork containing encysted larvae is ingested. The larvae are digested out of the meat in the stomach and attach to the wall of the small intestine. The adult worms mature in about 5-12 weeks and begin to produce proglottids containing infective eggs. These eggs are passed in the stool to the environment where the cycle is continued. |
SAMPLE 06-N Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Blastocystis hominis | 140/149 | 94 | 09/10 | Correct |
| Endolimax nana | 04 | 03 | 0 | Incorrect |
| NO PARASITES SEEN | 03 | 02 | 0 | Incorrect |
| Dientamoeba fragilis | 02 | 01 | 0 | Incorrect |
| Giardia lamblia | 01 | 0.6 | 0 | Incorrect |
| Chilomastix mesnili | 01 | 0.6 | 0 | Incorrect |
| Loa loa | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Blastocystis hominis was the correct response (94 and 90%). Quality control examination of 4% of this sample showed organisms in nearly every 100X high powered field. The organisms are highly variable in size and staining quality.
DIAGNOSTIC CHARACTERISTICS
 |
Blastocystis hominis is distributed worldwide and its classification remains unclear. It is for this reason that we ask that you report Blastocystis hominis only when "All Parasites" is requested. Organisms range in size from 6-40 microns and are characterized by a large central body with a rim of cytoplasm that contains nuclei and inclusion bodies. On a permanently stained smear the central body takes on a green color while the nuclei and other inclusion bodies stain red. The pathogenicity of this organism is still unresolved. |
SAMPLE 06-O Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Loa loa | 118/145 | 81 | 09/10 | Correct |
| No Parasites Seen | 12 | 08 | 1 | Incorrect |
| Mansonella sp. | 11 | 08 | 0 | Incorrect |
| Wuchereria bancrofti | 02 | 01 | 0 | Incorrect |
| Brugia malayi | 01 | 0.7 | 0 | Incorrect |
| Blastocystis hominis | 01 | 0.7 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Loa loa was the correct response (81 and 90%). Quality control examination of 4% of this sample revealed an average of 5 microfilariae per slide.
DIAGNOSTIC CHARACTERISTICS
 |
Loa loa also called the African eye worm, infects humans when they are bitten by infected deer or mango flies. The larvae are deposited into the bite wound and develop into adults within 6-12 months. Adults migrate beneath the conjunctiva or the skin, or through subcutaneous tissues. Years after the initial infection the adults give rise to microfilariae which can be detected in the blood. The microfilariae are sheathed and measure between 250-300 microns. They have nuclei that extend all the way to the tip of the tail. Although the sheath does not stain with giemsa it is still clearly visible as shown in the images on the left. |
IMMUNOASSAY RESULTS
CRYPTOSPORIDIUM IMMUNOASSAY RESULTS
| METHOD | 06-K | 06-L | 06-M | ||||
| NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | ||
| BD ColorPAC | 10 | 0 | 10 | 0 | 10 | 0 | |
| MCC Para-Tect Crypto/Giardia DFA | 01 | 0 | 01 | 0 | 0 | 0 | |
| Meridian ImmunoCard STAT Crypto/Giardia | 08 | 01 | 09 | 0 | 07 | 0 | |
| Meridian Merifluor Crypto/Giardia | 19 | 0 | 18 | 0 | 19 | 0 | |
| Remel ProSpecT Crypto EIA | 22 | 01 | 23 | 0 | 17 | 04 | |
| Remel Xpect Crypto | 01 | 0 | 01 | 0 | 01 | 0 | |
| TechLab/Wampole Test EIA | 05 | 0 | 05 | 0 | 04 | 0 | |
| Other | 01 | 0 | 01 | 0 | 01 | 0 |
GIARDIA IMMUNOASSAY RESULTS
| METHOD | 06-K | 06-L | 06-M | ||||
| NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | ||
| BD ColorPAC | 10 | 0 | 10 | 0 | 17 | 0 | |
| MCC Para-Tect Crypto/Giardia DFA | 01 | 0 | 01 | 0 | 01 | 0 | |
| Meridian ImmunoCard STAT Crypto/Giardia | 09 | 0 | 09 | 0 | 09 | 0 | |
| Meridian Merifluor Crypto/Giardia | 09 | 0 | 09 | 0 | 09 | 0 | |
| Meridian Premier Giardia | 01 | 0 | 01 | 0 | 0 | 02 | |
| Remel ProSpecT Giardia EIA | 34 | 0 | 31 | 0 | 08 | 22 | |
| Remel ProSpecT Giardia EZ | 02 | 0 | 02 | 0 | 02 | 0 | |
| Remel ProSpecT Giardia Rapid | 01 | 0 | 01 | 0 | 0 | 01 | |
| Remel Xpect Giardia EZ | 02 | 0 | 02 | 0 | 02 | 0 | |
| Remel Xpect Giardia/Crypto | 01 | 0 | 01 | 0 | 01 | 0 | |
| TechLab/Wampole Test EIA | 06 | 0 | 05 | 01 | 04 | 01 |
February 2006 DISTRIBUTION OF SCORES
| SCORE | NO. OF LABS | PERCENT |
| 100 | 114 | 66 |
| 90-99 | 03 | 02 |
| 80-89 | 35 | 22 |
| 70-79 | 02 | 01 |
| 60-69 | 09 | 06 |
| 50-59 | 01 | 0.6 |
| 40-49 | 02 | 01 |
| 20-29 | 01 | 0.6 |
GRADING
The answer key was derived from the response of all participating laboratories as per CLIA Regulations,Part 493, Subpart I, Section 493.917. These regulations can be viewed at www.phppo.cdc.gov These regulations state that 80% or more of participating laboratories or referee laboratories must identify the parasite for it to be correct. Similarly, less than 20% of the participating laboratories or referees finding parasites or ova is an incorrect response. Organisms reported by 20-80% of the participating laboratories or referees are "Unauthenticated", and are not considered for grading.
Each sample has a maximum value of 20 points. Credit is given according to the formula:
|
Number of correct responses by lab
# Correct Parasites Present + # Lab's Incorrect Answers |
X 100 |
IMPORTANT REMINDERS
The next Parasitology Proficiency Test is scheduled for June 05, 2006. You are responsible for notifying us before June 12, 2006 if you do not receive your test. Proficiency test results must be postmarked by June 19, 2006 or you will receive a zero. These requirements are clearly stated in your NYS Proficiency Testing Handbook provided by the NYS Clinical Laboratory Evaluation Program or can be accessed via the internet at www.wadsworth.org/labcert/clep/ProgramGuide/WebGuide.pdf.
NEWS AND NOTES
Policy changes made by the Clinical Laboratory Evaluation Program now allow for the CQ holder for a particular category to sign the attestation statement instead of the Laboratory Director. Starting with the February 05, 2001 test event we will now accept Director's and/or CQ holder's signatures on the attestation statement.
The Clinical Parasitology Lab of the NYSDOH offers two mailing kits for the submission of specimens. One kit contains vials of PVA and Formalin and the other does not. These kits can be ordered by calling 518-474-4175 and requesting kit DOH-2117. Please be sure to specify whether you need preservatives or not. Remember that the NYS Parasitology Lab only accepts specimens preserved in appropriate fixatives for the test requested.
Two one day Malaria Workshops are scheduled for April 11 and 12, 2006. These workshops will be presented in conjunction with the NLTN and will be held at Long Island University C.W. Post Campus in Brookville, NY. Registrations were sent to all permitted laboratories. For further information call 800-536-NLTN or visit NLTN web site.
On November 2, 2006 at the Marriott Hotel in Albany, NY, the NYS Parasitology Laboratory will provide a half day workshop on the Review of Intestinal Parasites at the Region I ASM Meeting hosted by the Eastern New York Branch of ASM.
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