Parasitology Proficiency Testing Program
Parasitology PT Program
Parasitology PT Program
BBPO Critique For 06 February 2006
The purpose of the New York State Proficiency Testing Program in the category of Parasitology Blood Borne Parasites is to monitor the performance of applicant laboratories in detecting and identifying parasites on blood films.
Sample Preparation and Quality Control
All slides used in this test were prepared and stained by a commercial source. 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.
Answer Key
| SAMPLE | CORRECT ANSWERS | POINTS |
|---|---|---|
| 06B-K | NO PARASITES SEEN | 20 |
| 06B-L | Plasmodium malariae | 20 |
| 06B-M | Plasmodium falciparum | 20 |
| 06B-N | NO PARASITES SEEN | 20 |
| 06B-O | Plasmodium vivax | 20 |
TOTAL POSSIBLE POINTS 100
SAMPLE 06B-K
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | STATUS |
| NO PARASITES SEEN | 14/15 | 93 | Correct |
| No Response Given | 01/15 | 07 | Incorrect |
QUALITY CONTROL
Participating laboratories agreed that No Parasites Seen was the correct response (93%). Quality control examination of 4% of this sample showed erythrocytes of normal size and staining characteristics. Normal blood elements are present and exhibit typical staining characteristics. No inclusions are present but there are an abundance of platelets.
SAMPLE 06B-L
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | STATUS |
| Plasmodium malariae | 15/15 | 100 | Correct |
QUALITY CONTROL
Participating laboratories agreed that Plasmodium malariae was the correct response (100%). Quality control examination of 4% of this sample showed infected erythrocytes in every 8-10 oil emersion fields. The infected cells are not enlarged and no stippling was observed. The predominant stage seen was the mature trophozoite but all stages were seen. Staining quality is good.
DIAGNOSTIC CHARACTERISTICS
 |
Plasmodium malariae is the least common species of plasmodium to infect humans and is sporadic in distribution. It tends to infect older red blood cells and so the parasitemia is often low. The ring stage is short lived so it is not usually seen. The most common stages seen are mature trophozoites and schizonts. The infected cells are not enlarged and may actually be smaller than uninfected cells. There is no stippling. The trophozoites are not amoeboid and often appear as compact rounded or band forms with coarse, scattered pigment. The gametocytes are round and compact with a single, well defined chromatin. The pigment is scattered and coares and may appear to be peripherally distributed. The schizonts contain 6-12 merozoites usually arranged in a rosette although they may be in an irregular cluster. The pigment, in the schizont, is in concentrated mass. |
SAMPLE 06B-M
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | STATUS |
| Plasmodium falciparum | 13/15 | 87 | Correct |
| Babesia sp. | 01/15 | 07 | Incorrect |
| No Response Given | 01/15 | 07 | Incorrect |
QUALITY CONTROL
Participating laboratories agreed that Plasmodium falciparum was the correct response (87%). Quality control examination of 4% of this sample showed infected erythrocytes in every 4-5 oil emersion fields. The infected cells are not enlarged and no stippling is observed. The predominant stage seen was the ring stage trophozoite but mature trophozoites and gametocytes were also seen. Staining quality is good.
DIAGNOSTIC CHARACTERISTICS
 |
Plasmodium falciparum is one of the four species of Plasmodium know 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 see 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. The mature trophozoites are compact with a mass or a few grains of coarse pigment. Gametocytes are rounded to banana-shaped and contain a single well defined chromatin and coarse rice-grain like pigment. The presence of pigment and gametocytes rules out Babesia sp. as a possibility. |
SAMPLE 06B-N
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | STATUS |
| NO PARASITES SEEN | 14/15 | 93 | Correct |
| No Response Given | 01/15 | 07 | Incorrect |
QUALITY CONTROL
Participating laboratories agreed that No Parasites Seen was the correct response (93%). Quality control examination of 4% of this sample showed erythrocytes of normal size and staining characteristics. Normal blood elements are present and exhibit typical staining characteristics. No inclusions are present.
SAMPLE 06B-O
RESULTS OF PARTICIPATING LABS
| ORGANISM | NUMBER REPORTED | PERCENT REPORTED | STATUS |
| Plasmodium vivax | 12/15 | 80 | Correct |
| Babesia sp. | 01/15 | 07 | Incorrect |
| Plasmodium falciparum and Plasmodium malariae | 01/15 | 07 | Incorrect |
| No Response Given | 01/15 | 07 | Incorrect |
QUALITY CONTROL
Participating laboratories agreed that Plasmodium vivax was the correct response (80%). Quality control examination of 4% of this sample showed parasites in every 4-5 oil emersion fields. Cells are enlarged and Schüffner's stippling is present. The stages seen include rings, amoeboid trophozoites and gametocytes. Pigment is scattered and fine.
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 stain paler than uninfected ones. They may also contain Schüffner's dots. The trophozoites are generally amoeboid with broken cytoplasm and have a single chromatin. Occasionally cells will contain more than one parasite. Mature schizonts contain 12-24 merozoites and the pigment is in a loose mass. The gametocytes are large, round and fill the entire cell. They contain a single well defined chromatin and the pigment is scattered and fine. |
FEBRUARY DISTRIBUTION OF SCORES
| SCORE | NO. OF LABS | PERCENT |
| 100 | 11 | 73 |
| 80 | 3 | 20 |
| 20 | 1 | 07 |
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. Registration forms have been 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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