A tourniquet test determines capillary fragility. It is a clinical diagnostic method to determine a patient's haemorrhagic tendency. It assesses fragility of capillary walls and is used to identify thrombocytopenia. The test is part of the WHO algorithm for diagnosis of dengue fever.

What is tourniquet test and how it is performed?

This test is performed by inflating a blood pressure cuff on the upper arm to midway between diastolic and systolic blood pressures for 5 minutes. The results are considered to be positive if more than 20 petechiae per square inch are observed on the skin in the area that was under pressure.

What is tourniquet test used for?

The tourniquet test (TT) is a physical examination technique that can identify and stratify dengue disease. Infection with DENV may result in increased capillary permeability, a physiological state that the TT exploits by applying sustained pressure to these small vessels.

How do you perform a tourniquet test?

1. Take the patient's blood pressure and record it, for example, 100/70.
2. Inflate the cuff to a point midway between SBP and DBP and maintain for minutes. ( ...
3. Reduce and wait 2 minutes.
4. Count petechiae below antecubital fossa. ...
5. A positive test is 10 or more petechiae per 1 square inch.

Is tourniquet test painful?

Ischemic pain is elicited by having the subject squeeze a handspring exercises 20 times after a tourniquet is inflated around his upper arm. The quality of sensation is dull-aching or stinging muscular pain, which closely resembles most types of pathologic pain, but increases progressively after cessation of squeezing.

Tourniquet Test (Capillary Fragility Test)

When is a tourniquet test done?

The test is part of the WHO algorithm for diagnosis of dengue fever. A blood pressure cuff is applied and inflated to the midpoint between the systolic and diastolic blood pressures for five minutes. The test is positive if there are more than 10 to 20 petechiae per square inch.

Which test is for dengue?

For patients presenting during the first week after fever onset, diagnostic testing should include a test for dengue virus (rRT-PCR or NS1) and IgM. For patients presenting >1 week after fever onset, IgM detection is most useful, although NS1 has been reported positive up to 12 days after fever onset (Figure 3-01).

What is the confirmatory test for dengue?

If an initial IgM antibody test is positive, a second test called the Plaque Reduction Neutralization Test (PRNT) is used to confirm the presence of antibodies to dengue virus and to help rule out other viral infections.

What is DSS in dengue?

Dengue Shock Syndrome (DSS) is the final stage of the more severe occurrence of dengue – Dengue Haemorrhagic Fever (DHF), and is fatal without prompt treatment. DHF is a severe form of dengue which affects blood and lymph vessels, and if untreated can lead to a failure of the circulatory system.

What are the warning signs of dengue?

• Abdominal pain or tenderness.
• Persistent vomiting.
• Clinical fluid accumulation.
• Mucosal bleed.
• Lethargy or restlessness.
• Liver enlargement > 2 cm.
• Laboratory finding of increasing HCT concurrent with rapid decrease in platelet count.

What is the principle of the capillary fragility test?

Capillary fragility test

A blood pressure cuff is applied and inflated to a point between the systolic and diastolic blood pressures for 5 min. The test is positive if there are 10 or more petechiae per square inch.

What is Rumpel Leede phenomenon?

Rumpel-Leede (R-L) phenomenon is the rare event in which the small dermal capillaries of an extremity rupture in response to application of a compressive device to that extremity, such as when inflating a cuff during noninvasive blood pressure monitoring or when applying a tourniquet to draw blood.

How does dengue rash look like?

A flat, red rash may appear over most of the body 2 to 5 days after the fever starts. A second rash, which looks like the measles, appears later in the disease. Infected people may have increased skin sensitivity and are very uncomfortable.

What are the other methods for capillary fragility test?

In the out-patient dispensary, the physical examination, the blood pressure ci4ff test or the completely variable "flicking" test are used as methods of evaluating the degree of capillary fragility.

Why platelets are low in dengue?

When an infected mosquito bites a human, the dengue virus enters the bloodstream, it binds to platelets and replicates leading to multiplication of infectious virus. The infected platelet cells tend to destroy normal platelets which is one of the major causes for the drop in the platelet count in dengue fever.

Does BP drop in dengue?

Mild dengue fever causes a high fever and flu-like symptoms. The severe form of dengue fever, also called dengue hemorrhagic fever, can cause serious bleeding, a sudden drop in blood pressure (shock) and death.

What is the critical stage of dengue?

The critical phase of dengue begins at defervescence and typically lasts 24–48 hours. Most patients clinically improve during this phase, but those with substantial plasma leakage can, within a few hours, develop severe dengue as a result of a marked increase in vascular permeability.

What is the WBC count in dengue?

Dengue fever is characterized by leucopenia (White Blood Cells (WBC) < 5000 cells/mm³), thrombocytopenia (< 150,000 cells/mm³), rising haematocrit (5–10%) and there should be no evidence of plasma leakage [10].

What does dengue antigen positive mean?

Positive: The presence of dengue nonstructural protein 1 (NS1) antigen is consistent with acute-phase infection with dengue virus. The NS1 antigen is typically detectable within 1 to 2 days following infection and up to 9 days following symptom onset.

What is IgG in dengue test?

IgG as a sero-marker of Dengue infection.

If the IgG is positive but the IgM is low or negative, then it is likely that the patient had an infection sometime in the past.

What is the cost of dengue test?

Cost of Dengue Test

In most of the cities dengue test price ranges between ₹1100-₹2000 depending upon the facilities, services and technology (manual, semi-automated, fully-automated) that the lab provides. .

How much platelet count is normal in dengue?

A typical person has a platelet count of between 150,000 and 250,000 per microlitre of blood. About 80 to 90 per cent of patients with dengue will have levels below 100,000, while 10 to 20 per cent of patients will see critically low levels of 20,000 or less.

Can I have dengue without fever?

An overwhelming 75 – 90% of patients acquire dengue fever without any symptoms, not even fever.

What is the clinical significance of a positive result in capillary fragility test?

Positive capillary fragility or positive tourniquet tests are terms used loosely to describe intracutaneous hemorrhage produced by standardized doses of trauma (suction or venous compression). These tests for capillary fragility are crude and cannot be performed accurately by counting petechiae.

What are the complications of dengue fever?

• seizures.
• brain damage.
• blood clots.
• damage to the liver and lungs.
• heart damage.
• shock.
• death.