- Author: Derek Ryan Linklater, MD; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD more...
Laboratory studies that may be used in the diagnosis of diphyllobothriasis include the following:
Microscopic stool examination for ova and parasites 
Complete blood count (CBC) - Eosinophilia may be present
Hemoglobin level and hematocrit - These may be below or at the lower end of the reference range
Mean cell volume - This may be above or at the higher end of the reference range
Vitamin B-12 level
Diagnosis of D latum infection is based on identification of the operculated eggs in the stool (see the images below). Usually, this is not difficult, because of the large quantity of eggs (≥1 million) produced each day.
The anemia produced by diphyllobothriasis is typically associated with increased free hydrochloric acid in gastric juice, in contrast to the relative achlorhydria invariably observed in true pernicious anemia.
A multiplex polymerase chain reaction (PCR) has been described.
In general, no imaging studies are required to evaluate diphyllobothriasis, unless they are clinically indicated by other aspects of the patient’s presentation. For example, patients who present with obstruction require appropriate testing, starting with both flat and upright abdominal radiography.
On occasion, cases of diphyllobothriasis have been successfully identified by means of capsule endoscopy.[7, 8] This procedure is painless and may provide useful adjunctive information for the treatment of this disease.
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