Table 74.
Summary of Tests for Trypanosomes
| Diagnostic Procedures | Optimum Specimen | Transport Considerations | Estimated TATa |
|---|---|---|---|
| Microscopy of Giemsa-stained thick and thin peripheral blood films in fresh and stained preparations. | Drop of blood from finger stick or venipuncture needle placed directly on glass slides and blood films made immediately OR Buffy coat concentrate from anticoagulated venous blood (thin smear or fresh wet prep for motile organisms) |
Slides and wet preps should be made from blood within 1 h. Thick blood films dry slowly and should be protected from inadvertent smearing or spillage and dust. Use of the “scratch” method will improve adherence and allow for examination as soon as the blood is visibly dry. |
2–4 h |
| Microscopic examination of tissue aspirates/biopsies by Giemsa/H&E stains | Fluid from needle aspirate of enlarged lymph nodes or tissue biopsies from lymph nodes, skin lesions, heart, GI tract, or other organ |
Fresh aspirated fluid should be stained and examined as soon as possible, preferably within 1 h of sampling. | 2 h–3 d |
| Culture in NNN or other suitable media with subsequent microscopic examination for motile trypanosomes | Anticoagulated blood or buffy coat, tissue aspirates, and tissue biopsies | Fresh specimens should be inoculated into culture medium as soon as possible, preferably within 1 h of collection for preservation of organism viability. | 2–6 d |
| Serology | 1.0 mL of serum from clotted blood. Plasma is also acceptable for the Ortho donor test. | Serum or plasma should be separated from blood within several hours. Store serum refrigerated or frozen if not tested within 4–6 h to preserve antibody and prevent bacterial growth. Avoid use of hyperlipemic or hemolyzed blood. | 1 d |
| NAAT | Typically 1.0 mL venipuncture blood in EDTA tube | Test should be performed as soon as possible, but blood may be transported refrigerated over 48 hours. | 1–2 h |
Abbreviations: EDTA, ethylenediaminetetraacetic acid; GI, gastrointestinal; H&E, hematoxylin & eosin; NAAT, nucleic acid amplification test; NNN, Novy-MacNeal-Nicolle; TAT, turnaround time.
aTransportation time and nucleic acid extraction time are not included in this estimate.