Parasitology Proficiency Testing Program
Parasitology PT Program
Parasitology PT Program
GENERAL CRITIQUE FOR 06 June 2005
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 June 2005
| SAMPLE | CORRECT ANSWERS | POINTS |
|---|---|---|
| 06-A | Trichuris trichiura | 20 |
| 06-B | Giardia lamblia | 20 |
| 06-C | Paragonimus westermani | 20 |
| 06-D | Endolimax nana | 20 |
| 06-E | Plasmodium vivax | 20 |
TOTAL POSSIBLE POINTS 100
SAMPLE 06-A Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Trichuris trichiura | 158/158 | 100 | 10/10 | Correct |
| Entamoeba coli | 02 | 01 | 0 | Incorrect |
| Cryptosporidium sp. | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Trichuris trichiura was the correct response (100%). Quality control examination of 4% of this sample revealed an average of 9 ova per coverslip. No other organisms were observed. 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
 |
Trichuris trichiura has a worldwide distribution but is more prevalent in warm moist climates. The diagnosis is made by seeing the characteristic eggs in stool. The average egg measures 55 x 25 microns and is barrel-shaped. They have a smooth, thick, brownish shell with polar plugs at each end. Infection occurs when eggs in the soil are ingested. The larvae emerge in the intestine where they mature. Adult worms may live for up to 10 years or longer and continue to pass eggs into the environment. |
SAMPLE 06-B Report Protozoa Only
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Giardia lamblia | 157/158 | 99 | 10/10 | Correct |
| Chilomastix mesnili | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Giardia lamblia was the correct response (99 and 100%). Quality control examination of 4% of this sample revealed cysts in almost every 40X field. No other organisms were observed. 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
 |
Giardia lamblia is the most commonly diagnosed flagellate in humans. It has a worldwide distribution and is more prevalent in children than in adults. Trophozoites are pear shaped and measure 10-20 microns. They have 2 nuclei, 4 pair of flagella, 2 axonemes, and 2 median bodies. The infective cysts are oval and measure 11-15 microns. They contain 4 nuclei usually located at one end, filaments, and median bodies. Infection occurs via the fecal-oral route. |
SAMPLE 06-C Report Helminths Only
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Paragonimus westermani | 155/158 | 98 | 10/10 | Correct |
| Fasciola hepatica/Fasciolopsis buski | 02 | 01 | 0 | Incorrect |
| Diphyllobothrium latum | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Paragonimus westermani was the correct response (98 and 100%). Quality control examination of 4% of this sample revealed an average of 20 ova per coverslip. No other organisms were observed. 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
 |
The diagnostic stage of Paragonimus westermani is the characteristic egg found in stool or sputum. These eggs are yellow-brown, ovoid, and have a prominent operculum. They measure 80-120 microns by 45-70 microns and have a thickened shell at the abopercular end. Humans become infected when they ingest uncooked shellfish containing metacercariae. These metacercariae excyst in the duodenum and migrate into the lungs where they mature and release their eggs into the sputum. The eggs are then coughed up and released into the environment or swallowed and passed in the feces. |
SAMPLE 06-D Report Protozoa Only
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Endolimax nana | 138/157 | 88 | 09/10 | Correct |
| No Parasites Seen | 18 | 11 | 01 | Incorrect |
| Entamoeba hartmanni | 02 | 01 | 0 | Incorrect |
| Blastocystis hominis | 02 | 01 | 0 | Incorrect |
| Iodamoeba butschlii | 01 | 0.6 | 0 | Incorrect |
| Dientamoeba fragilis | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Endolimax nana was the correct response (88 and 90%). Quality control examination of 4% of this sample showed cysts and trophozoites in every 8-10 100X oil emersion fields. Blastocystis hominis was also present in this sample but should not have been reported because "All Parasites" was not requested.
DIAGNOSTIC CHARACTERISTICS
 |
Endolimax nana is distributed worldwide and is nonpathogenic. The trophozoites measure 6-12 microns and have a single nucleus with a large karyosome and no peripheral chromatin. Cysts of Endolimax nana measure 5-10 microns, are round to oval, and contain four nuclei. Infection occurs by ingesting contaminated food or water. |
SAMPLE 06-E Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Plasmodium vivax | 132/151 | 87 | 08/10 | Correct |
| Plasmodium ovale | 14 | 09 | 02 | Incorrect |
| Plasmodium malariae | 05 | 03 | 0 | Incorrect |
| Plasmodium sp. | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Plasmodium vivax was the correct response (87 and 80%). Quality control examination of 4% of this sample revealed parasites in every 3-4 oil emersion fields. Infected red blood cells are enlarged and Schüffner's stippling is present. Stages seen include rings, amoeboid trophozoites, and gametocytes. Polymerase Chain Reaction (PCR) analyses for the four species of human malaria were performed. They were negative for Plasmodium falciparum, malariae, and ovale and positive for Plasmodium vivax
DIAGNOSTIC CHARACTERISTICS
 |
Plasmodium vivax is the most common species of malaria to infect humans. It may account for as much as 80% of all malaria cases. It also has the widest distribution. Infected red cells are usually enlarged and may stain paler than uninfected ones. They may also contain Schüffner's dots. The trophozoites are generally amoeboid and have a large chromatin. Occasionally cells will contain more than one parasite. Mature schizonts contain 12-24 merozoites and gametocytes are round and fill the entire cell. Pigment is fine and scattered. |
IMMUNOASSAY RESULTS
CRYPTOSPORIDIUM IMMUNOASSAY RESULTS
| METHOD | 06-A | 06-B | 06-C | ||||
| NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | ||
| BD ColorPAC | 12 | 0 | 12 | 0 | 12 | 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 | 20 | 0 | 20 | 0 | 20 | 0 | |
| Remel ProSpecT Crypto EIA | 26 | 0 | 26 | 0 | 24 | 0 | |
| Remel Xpect Crypto | 01 | 0 | 01 | 0 | 01 | 0 | |
| Remel Xpect Giardia/Crypto | 01 | 0 | 01 | 0 | 01 | 0 | |
| TechLab Crypto Cel IF | 01 | 0 | 01 | 0 | 01 | 0 | |
| TechLab/Wampole Test EIA | 04 | 0 | 04 | 0 | 03 | 0 | |
| Other | 01 | 0 | 01 | 0 | 01 | 0 |
GIARDIA IMMUNOASSAY RESULTS
| METHOD | 06-A | 06-B | 06-C | ||||
| NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | ||
| BD ColorPAC | 14 | 0 | 0 | 14 | 14 | 0 | |
| MCC Para-Tect Crypto/Giardia DFA | 01 | 0 | 0 | 01 | 01 | 0 | |
| Meridian ImmunoCard STAT Crypto/Giardia | 09 | 0 | 0 | 09 | 09 | 0 | |
| Meridian Merifluor Crypto/Giardia | 14 | 0 | 0 | 14 | 14 | 0 | |
| Remel ProSpecT Giardia EIA | 36 | 0 | 0 | 36 | 35 | 0 | |
| Remel ProSpecT Giardia EZ | 03 | 0 | 0 | 03 | 03 | 0 | |
| Remel ProSpecT Giardia Rapid | 02 | 0 | 0 | 02 | 01 | 0 | |
| Remel Xpect Giardia/Crypto | 01 | 0 | 0 | 01 | 01 | 0 | |
| TechLab/Wampole Test EIA | 05 | 0 | 0 | 05 | 04 | 0 | |
| Other | 01 | 0 | 0 | 01 | 01 | 0 |
June 2005 DISTRIBUTION OF SCORES
| SCORE | NO. OF LABS | PERCENT |
| 100 | 122 | 74 |
| 90-99 | 08 | 05 |
| 80-89 | 24 | 15 |
| 70-79 | 01 | 0.6 |
| 60-69 | 08 | 05 |
| 40-49 | 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 October 03, 2005. You are responsible for notifying us before October 10, 2005 if you do not receive your test. Proficiency test results must be postmarked by October 17, 2005 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.
A Malaria Workshop is scheduled for September 08, 2005 at the Albany College
of Pharmacy, Albany, NY. Registration forms were sent to all permitted
laboratories. Registration deadline is August 31, 2005.
Molecular Techniques: A Wet Workshop will be offered October 24-28, 2005 in Albany, New York.
For further information or additional registration forms call 800-536-NLTN or visit
NLTN web site.
Web site questions or comments or to request a different file
format (pdf.,doc.,wpd.) contact:
E-mail: Parasit@wadsworth.org.