Chapter 10: ClinicalLaboratory Procedures Case Study

A request for “ovaand parasites” was received in the laboratory in the lateafternoon. The specimen consisted of one polyvinyl alcohol (PVA)vial and one 10% formalin vial. The specimen label included thepatient’s name, the doctor’s name, and the date collected. Therewas a note attached requesting “special attention for amoeba.” Thetechnologist noted that the specimen vials contained material thatwas yellowish, opaque, and appeared chalky looking.

1. The medical laboratory scientist (MLS) checked the patient’shistory and found that he had been scheduled for a lower G.I. tractx-ray series that morning. What conclusion would be drawn from thisinformation and what action should be taken?
   1. Process the specimen as usual.

1. Reject the specimen; barium is present in the specimen.

1. Reject the specimen; identification information isincomplete.

1. Reject the specimen for reasons B and C.

1. What effect does barium have on the specimen?

1. It makes observation of parasites impossible.

1. It kills all eggs, cysts, and trophozoites.

1. It makes the specimen hazardous for workers.

1. 1. It confuses the MLS because it looks like yeast.
2. A week later, a new and properly labeled specimen arrived forparasite examination at 2 p.m.

The collection timeon the unpreserved liquid specimen was 9 a.m. The comment on theorder stated, “Rule out Giardiasis.” How should the MLS handle thisspecimen?

1. Process as usual; a proper specimen was submitted.

1. Immediately look for trophozoites in a wet mount.
2. Process as usual, noting that trophozoites might not be visiblebecause the sample was not submitted when collected.
3. Reject the specimen because it was not preserved whencollected.

1. Two days later a new, fresh, correctly labeled specimen and aPVA tube containing the patient’s feces were submitted forparasitic examination. The specimen, collected at 10 a.m., arrivedin the laboratory at 10:30 a.m. Select the correct sequence used toproperly process this specimen.
   1. Prepare smears for trichrome and modified acid-fast stains;concentrate and read results from 10% formalin preparation; stainand read the trichrome smears.
   2. Prepare and read the direct mount made from fresh feces;prepare trichrome smears from the PVA tube; concentrate and readresults from the PVA tube.
   3. Concentrate and read results from 10% formalin preparation;prepare and read the direct mount made from fresh feces; prepare,stain, and read the trichrome smears from the PVAtube.
   4. Prepare and read the direct mount made from fresh feces;prepare smears for trichrome and modified acid-fast stains;concentrate and read results from 10% formalin preparation; stainand read the trichrome and acid-fast smears.