Dengue Procedure

Question 1

SPECIMEN CONSIDERATIONS
WHOLE BLOOD
• Use venipuncture to collect blood into tubes containing anticoagulants (3).

Answer 1

heparin, EDTA, sodium citrate

Question 2

Specimen

• Storage:
• Refrigerate at____ if not tested immediately.
• Must be tested within____ days if stored at this temperature.

Answer 2

2-8°C

3

Question 3

Specimen

Important Precautions:
• Do not use blood specimens stored for over____ days to avoid nonspecific reactions.
• Allow specimens to _____before testing.

Answer 3

3

reach room temperature (15-30°C)

Question 4

NS1 positive

Answer 4

• Acute dengue infection.

The NS1 antigen is present in the blood during the early phase of dengue infection.

Question 5

IgM positive

Answer 5

Primary dengue infection.

IgM antibodies are produced early in dengue infection, and a negative IgG result suggests that it is a first-time infection.

Question 6

IgM IgG positive

Answer 6

Secondary dengue infection.

The presence of both IgM and IgG antibodies indicates a previous exposure to dengue virus.

Question 7

IgG positive

Answer 7

Past dengue infection.

IgG antibodies can persist for life after a dengue infection, indicating a past infection.

Question 8

TEST LIMITATIONS
• Variability in Antigen/Antibody Levels
• Levels of NS1 antigen, IgG, and IgM antibodies depend on the______.

• Early or secondary infections may show____ levels.

• Antibodies may not be detectable within the_____ post-infection.

• Recommendation: If symptoms persist with a negative result, collect a second specimen_____ later.

Answer 8

disease stage

low IgM

first 7-10 days

3-4 days

Question 9

THE DENGUE DUO TEST
TEST LIMITATIONS
• False-Negative Results:

Answer 9

• May occur if NS1 antigen or antibodies are absent or below detectable levels at collection.

• A negative result does not rule out dengue infection.

Question 10

LIMITATIONS

• Contextual Interpretation:
Test results must be evaluated alongside other clinical data.

Question 11

TEST LIMITATIONS
• Cross-reactivity:
• Serological cross-reactivity with other Flavivirus genus members (e.g.,3) is possible.

• Internal studies showed no cross-reactivity, but it cannot be excluded

Answer 11

Zika
West Nile
Japanese Encephalitis

Question 12

TEST LIMITATIONS

• Test variability:
• Results may vary due to: (5)

These factors should be considered when comparing studies.

Answer 12

• Timing of specimen collection.
• Specimen type!
• Serotype distribution.
• Reference method used.
• Population factors.