Parasitology Proficiency Testing Program
Parasitology PT Program
Parasitology PT Program
GENERAL CRITIQUE FOR 05 JUNE 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 05 JUNE 2006
| SAMPLE | CORRECT ANSWERS | POINTS |
|---|---|---|
| 07-A | Diphyllobothrium latum | 20 |
| 07-B | Ascaris lumbricoides | 20 |
| Cryptosporidium sp. | ||
| 07-C | Trichuris trichiura | 20 |
| 07-D | NO PARASITES SEEN | 20 |
| 07-E | Trypanosoma cruzi | 20 |
TOTAL POSSIBLE POINTS 100
SAMPLE 07-A Report Helminths Only
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Diphyllobothrium latum | 138/138 | 100 | 10/10 | Correct |
QUALITY CONTROL
Participating and referee laboratories agreed that Diphyllobothrium latum was the correct response (100%). Quality control examination of 4% of this sample revealed an average of 40 ova per coverslip. Blastocystis hominis and Endolimax nana 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
 |
Diphyllobothrium latum is an intestinal tapeworm acquired by ingesting raw or poorly cooked freshwater fish. The diagnostic stage is the egg recovered in stool. These eggs are ovoid and measure 60-70 microns by 20-35 microns. They have an operculum at one end and a small knob at the other. The knob may or may not be visible depending upon the position of the egg. These eggs may be confused with Paragonimus sp. so measurement with a calibrated ocular micrometer is important. |
SAMPLE 07-B Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Ascaris lumbricoides | 135/138 | 98 | 10/10 | Correct |
| Cryptosporidium sp. | 99 | 72 | 08 | Correct |
| Blastocystis hominus | 79 | 57 | 05 | No Penalty |
| Endolimax nana | 01 | 01 | 0 | No Penalty |
QUALITY CONTROL
Participating and referee laboratories agreed that Ascaris lumbricoides(98 and 100%) and Cryptosporidium sp. (74 and 80%) were the correct responses. Quality control examination of 4% of this sample showed an average of 18 ova per coverslip. Blastocystis hominis and Endolimax nana were also present and so no credit was deducted for reporting either of these organisms. Other tests performed include Direct Immunofluorescent Assay and ELISA for Giardia lamblia and Cryptosporidium sp. which were negative for Giardia lamblia and positive for Cryptosporidium sp.. A modified acid-fast stained smear was also positive for Cryptosporidium sp..
DIAGNOSTIC CHARACTERISTICS
 |
Ascaris lumbricoides is one of the most common intestinal nematode infections of man. It is most prevalent in warm moist climates but can also be found in cooler areas. Infection is acquired when embryonated eggs in contaminated soil are ingested. The fertilized eggs are round to oval, mammillated, and golden brown in color. They measure 45-75 microns by 35-50 microns. Occasionally they may lose their outer mammillated layer. Infertile eggs are larger, less broad, and have thinner shells. They measure 85-90 microns by 43-47 microns. |
 |
Cryptosporidium sp. has become one of the most important opportunistic infections seen in the immunocompromised patient. This coccidian parasite is spread through contaminated food or water. The diagnostic stage is the oocyst passed in the stool. On a modified acid-fast stained smear these oocyst measure 4-5 microns and stain pale to deep pink. It is sometimes possible to see the 4 sporozoites within the oocyst. Other methods of diagnosis include immunoassays and immunofluorescent stains. |
SAMPLE 07-C Report Helminths Only
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Trichuris trichiura | 138/138 | 100 | 10/10 | Correct |
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 21 ova per coverslip. Other tests performed include Direct Immunofluorescent Assay and ELISA for Giardia lamblia and Cryptosporidium sp. which were negative for both. 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 07-D Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| NO PARASITES SEEN | 128/138 | 93 | 10/10 | Correct |
| Entamoeba histolytica/dispar | 04 | 03 | 0 | Incorrect |
| Entamoeba hartmanni | 02 | 1.5 | 0 | Incorrect |
| Blastocystis hominis | 02 | 1.5 | 0 | Incorrect |
| Endolimax nana | 02 | 1.5 | 0 | Incorrect |
| Dientamoeba fragilis | 01 | 0.8 | 0 | Incorrect |
| Iodamoeba butschlii | 01 | 0.8 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that NO PARASITES SEEN was the correct response (93 and 100%). Quality control examination of 4% of this sample showed no organisms present. White blood cells are present and can be confused with amoebae.
DIAGNOSTIC CHARACTERISTICS
 |
White blood cells can sometimes be confused with amoebae. They can be distinguished primarily by examining their nuclei. The ratio of nuclear material to cytoplasm is about 1:1 in polymorphonuclear leukocytes (PMNs) and is about 1:10 in trophozoites of Entamoeba histolytica and 1:3 in cysts. The nuclei of PMNs are also segmented, connected by narrow bands of chromatin. The segments may sometimes appear as separate nuclei but by focusing up and down the connecting strands can usually be seen. |
SAMPLE 07-E Report All Parasites
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | REFEREE RESULTS | STATUS |
| Trypanosoma cruzi | 128/136 | 94 | 10/10 | Correct |
| Trypanosoma b. gambiense | 03 | 02 | 0 | Incorrect |
| Toxoplasma gondii | 03 | 02 | 0 | Incorrect |
| Plasmodium vivax | 01 | 0.7 | 0 | Incorrect |
QUALITY CONTROL
Participating and referee laboratories agreed that Trypanosoma cruzi was the correct response (94 and 100%). Quality control examination of 4% of this sample revealed organisms in every 10-15 oil fields.
DIAGNOSTIC CHARACTERISTICS
 |
Trypanosoma cruzi is the causative agent of the zoonosis Chagas' disease. It is a major health problem in Latin America. The organism is transmitted through the feces of the reduviid bug when it takes a blood meal. Trypomastigotes are detected in the blood on thin and thick smears. They measure approximately 20 microns and usually are C or U shaped. The nucleus is located in the middle of the organism and a large kinetoplast is located at the posterior end. A flagellum arises from the kinetoplast and follows the undulating membrane to the anterior end where it projects as a free flagellum. On giemsa stained smears the cytoplasm stains blueish while the nucleus and kinetoplast stain purple or red. |
IMMUNOASSAY RESULTS
CRYPTOSPORIDIUM IMMUNOASSAY RESULTS
| METHOD | 07-A | 07-B | 07-C | ||||
| NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | ||
| BD ColorPAC | 06 | 0 | 01 | 07 | 06 | 0 | |
| MCC Para-Tect Crypto/Giardia DFA | 01 | 0 | 0 | 01 | 01 | 0 | |
| Meridian ImmunoCard STAT Crypto/Giardia | 12 | 0 | 01 | 12 | 11 | 01 | |
| Meridian Merifluor Crypto/Giardia | 18 | 0 | 01 | 19 | 18 | 0 | |
| Remel ProSpecT Crypto EIA | 24 | 0 | 01 | 24 | 24 | 0 | |
| Remel Xpect Giardia/Crypto | 01 | 0 | 0 | 01 | 01 | 0 | |
| TechLab/Wampole Test EIA | 05 | 0 | 01 | 04 | 05 | 0 | |
| Other | 01 | 0 | 0 | 01 | 01 | 0 |
GIARDIA IMMUNOASSAY RESULTS
| METHOD | 07-A | 07-B | 07-C | ||||
| NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | NEGATIVE | POSITIVE | ||
| BD ColorPAC | 07 | 0 | 07 | 01 | 07 | 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 | 13 | 0 | 14 | 0 | 12 | 0 | |
| Remel ProSpecT Giardia EIA | 31 | 0 | 32 | 0 | 31 | 0 | |
| Remel ProSpecT Giardia EZ | 03 | 0 | 03 | 0 | 03 | 0 | |
| Remel Xpect Giardia | 03 | 0 | 03 | 0 | 03 | 0 | |
| Remel Xpect Giardia/Crypto | 01 | 0 | 01 | 0 | 01 | 0 | |
| TechLab/Wampole Test EIA | 06 | 0 | 06 | 0 | 06 | 0 | |
| Other | 01 | 0 | 01 | 0 | 01 | 0 |
June 2006 DISTRIBUTION OF SCORES
| SCORE | NO. OF LABS | PERCENT |
| 100 | 105 | 72 |
| 90-99 | 31 | 21 |
| 80-89 | 16 | 11 |
| 70-79 | 05 | 03 |
| 60-69 | 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 02, 2006. You are responsible for notifying us before October 10, 2006 if you do not receive your test. Proficiency test results must be postmarked by October 16, 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.
Molecular Techniques: A Wet Workshop will be offered October 16-20, 2006 in Albany, New York. Further information to follow.
A Clinical Diagnostic Workshop on Human Intestinal Parasites The NYS DOH, Wadsworth Center Parasitology Laboratory will offer training in the Diagnosis of Human Intestinal Parasites at the November 02, 2006 meeting of the Northeastern American Society of Microbiology Region I Branch in Albany, New York. This half-day workshop at the ASM branch meeting will update participants on new and emerging intestinal parasites, as well as diagnosis of traditional helminths and protozoa. Instruction will include notebooks, powerpoint talks, microscopic demonstrations, and bench aids from the World Health Organization. In addition, the workshop will discuss technical aspects of laboratory methods, trouble-shooting, and how to best utilize CDC's web-based DPDx that is available electronically. Information to be mailed.
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