Parasitology Proficiency Testing Program
Parasitology PT Program
Parasitology PT Program
GENERAL CRITIQUE FOR 03 October 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 03 October 2005
| SAMPLE | CORRECT ANSWERS | POINTS |
|---|---|---|
| 06-F | Hymenolepis nana | 20 |
| 06-G | Necator americanus/Ancylostoma duodenale | 20 |
| 06-H | NO PARASITES SEEN | 20 |
| 06-I | Entamoeba coli | 20 |
| 06-J | Plasmodium falciparum | 20 |
TOTAL POSSIBLE POINTS 100
SAMPLE 06-F Report Helminths Only
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Hymenolepis nana | 149/154 | 97 | 10/10 | Correct |
| Trichuris trichiura | 08 | 05 | 0 | Incorrect |
| Hymenolepis diminuta | 01 | 0.6 | 0 | Incorrect |
| Entamoeba histolytica | 01 | 0.6 | 0 | Incorrect |
| No Parasites Seen | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Hymenolepis nana was the correct response (97 and 100%). Quality control examination of 4% of this sample revealed an average of 8 ova per coverslip. Rare Entamoeba histolytica cysts are also present but should not have been reported because "Helminths 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
 |
Hymenolepis nana also known as the dwarf tapeworm is an intestinal cestode acquired by ingesting eggs from the environment or rarely by ingesting infected beetles. Internal autoinfection is also possible. H. nana is the only human tapeworm that doesn't have an intermediate host and transmission occurs from person to person. It has a worldwide distribution and is more commonly seen in children. The diagnostic stage is the egg recovered in stool. These eggs are spherical, thin shelled, and measure 30 to 47 microns in diameter. They have a six hooked oncosphere with two polar thickenings from which filaments arise. These filaments are visible in the space between the embryo and the outer shell. Eggs of H. nana can be confused with the eggs of Hymenolepis diminuta and careful measurement with a calibrated ocular micrometer is essential. The eggs of H. diminuta are much larger measuring 70-85 microns. |
SAMPLE 06-G Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Necator americanus/Ancylostoma duodenale | 153/154 | 99 | 10/10 | Correct |
| Blastocystis hominis | 35 | 23 | 03 | No Penalty |
| Entamoeba coli | 32 | 21 | 03 | No Penalty |
| Endolimax nana | 02 | 01 | 0 | Incorrect |
| Entamoeba hartmanni | 02 | 01 | 0 | Incorrect |
| Ascaris lumbricoides | 02 | 01 | 0 | Incorrect |
| Hymenolepis nana | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Hookworm was the correct response (99 and 100%). Quality control examination of 4% of this sample revealed an average of 6 ova per coverslip. Also present in rare numbers are Blastocystis hominis and Entamoeba coli 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
 |
Necator americanus(Hookworm) infection occurs in warm moist areas through skin penetration of filariform larvae from the soil. The larvae migrate through the heart and lungs, are swallowed, and take up residence in the small intestine where the adults mature. The diagnostic stage is the egg passed in stool. They are oval and measure approximately 60 X 40 microns. They have a thin shell with a space between the shell and the developing embryo. Development is usually at the 8 to 32 cell stage. These eggs are indistinguishable from those of Ancylostoma duodenale. |
SAMPLE 06-H Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| NO PARASITES SEEN | 152/154 | 99 | 10/10 | Correct |
| Cryptosporidium sp. | 01 | 0.6 | 0 | Incorrect |
| Necator americanus/Ancylostoma duodenale | 01 | 0.6 | 0 | Incorrect |
| Blastocystis hominis | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that NO PARASITES SEEN was the correct response (99 and 100%). Quality control examination of 4% of this sample revealed no parasites. 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.
SAMPLE 06-I Report Protozoa Only
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Entamoeba coli | 149/154 | 97 | 10/10 | Correct |
| No Parasites Seen | 03 | 02 | 0 | Incorrect |
| Entamoeba histolytica | 02 | 01 | 0 | Incorrect |
| Giardia lamblia | 01 | 0.6 | 0 | Incorrect |
| Plasmodium falciparum | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Entamoeba coli was the correct response (97 and 100%). Quality control examination of 4% of this sample showed organisms in every 8-10 100X oil emersion fields. The cysts measure between 10-20 microns and contain 5-8 nuclei.
DIAGNOSTIC CHARACTERISTICS
 |
Entamoeba coli is distributed worldwide and is nonpathogenic. The trophozoites vary in size from 15-50 microns with an average range of 20-25 micrometers. They have a single nucleus that generally has a large diffuse karyosome and irregular peripheral chromatin. The cytoplasm is generally granular and vacuolated. The cysts measure between 10-35 microns with an average range of 15-25 microns. Most of the cysts noted in this sample were in the 10-20 micron size range. The mature cysts have 8 nuclei that have uneven peripheral chromatin and large diffuse karyosomes. Chromatin bars are less common than in Entamoeba histolytica and have pointed ends. Infection occurs by ingesting contaminated food or water. |
SAMPLE 06-J Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Plasmodium falciparum | 138/151 | 91 | 10/10 | Correct |
| Babesiasp. | 07 | 05 | 0 | Incorrect |
| No Parasites Seen | 03 | 02 | 0 | Incorrect |
| Plasmodium vivax | 02 | 01 | 0 | Incorrect |
| Entamoeba coli | 01 | 0.6 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Plasmodium falciparum was the correct response (91 and 100%). Quality control examination of 4% of this sample revealed parasites in every 6-8 oil emersion fields. Infected red blood cells are not enlarged and do not contain Schüffner's stippling. The only stage observed is the ring stage trophozoite.
DIAGNOSTIC CHARACTERISTICS
 |
Plasmodium falciparum is one of the four species of Plasmodium known to infect humans. It causes the most dangerous and severe form of malaria and is always considered to be a medical emergency. Death may occur rapidly if proper treatment is not started immediately. Its distribution is limited to the tropics, primarily Africa and Asia. P. falciparum invades all ages of RBC's and so the parasitemia can exceed 50%. The usual stages seen in the peripheral blood are rings and gametocytes. Schizogony occurs in the internal organs so it is rare to seen other stages although they may be present in cases of severe malaria. The infected RBC's are not enlarged nor do they contain Schüffner's dots. The rings are generally small, and may have one or two chromatin dots. Applique´ forms are also characteristic. Gametocytes are rounded to banana-shaped and contain a single well defined chromatin and coarse rice-grain like pigment |
IMMUNOASSAY RESULTS
CRYPTOSPORIDIUM IMMUNOASSAY RESULTS
| METHOD | 06-F | 06-G | 06-H | ||||
| NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | ||
| BD ColorPAC | 11 | 0 | 12 | 0 | 12 | 0 | |
| MCC Para-Tect Crypto/Giardia DFA | 01 | 0 | 01 | 0 | 01 | 0 | |
| Meridian ImmunoCard STAT Crypto/Giardia | 08 | 0 | 09 | 0 | 09 | 0 | |
| Meridian Merifluor Crypto/Giardia | 20 | 0 | 14 | 0 | 20 | 0 | |
| Meridian Premier Crypto | 01 | 0 | 01 | 0 | 0 | 0 | |
| Remel ProSpecT Crypto EIA | 24 | 0 | 25 | 0 | 26 | 0 | |
| TechLab/Wampole Test EIA | 04 | 0 | 04 | 0 | 04 | 0 | |
| Other | 01 | 0 | 01 | 0 | 0 | 0 |
GIARDIA IMMUNOASSAY RESULTS
| METHOD | 06-F | 06-G | 06-H | ||||
| NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | ||
| BD ColorPAC | 13 | 0 | 14 | 0 | 14 | 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 | 14 | 0 | 14 | 0 | 14 | 0 | |
| Meridian Premier Giardia | 01 | 0 | 01 | 0 | 0 | 0 | |
| Remel ProSpecT Giardia EIA | 31 | 0 | 33 | 0 | 33 | 0 | |
| Remel ProSpecT Giardia EZ | 03 | 0 | 03 | 0 | 0 | 0 | |
| Remel Xpect Giardia/Crypto | 03 | 0 | 03 | 0 | 03 | 0 | |
| TechLab/Wampole Test EIA | 04 | 0 | 05 | 0 | 04 | 01 | |
| Other | 01 | 0 | 01 | 0 | 01 | 0 |
October 2005 DISTRIBUTION OF SCORES
| SCORE | NO. OF LABS | PERCENT |
| 100 | 125 | 78 |
| 90-99 | 11 | 07 |
| 80-89 | 20 | 12 |
| 70-79 | 01 | 0.6 |
| 60-69 | 01 | 0.6 |
| 40-49 | 02 | 01 |
| 20-39 | 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 February 06, 2006. You are responsible for notifying us before February 13, 2006 if you do not receive your test. Proficiency test results must be postmarked by February 21, 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. Registration forms will be sent to all permitted laboratories. For further information call 800-536-NLTN or visit NLTN web site.
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