Quick Facts
- Sample: Green-top sodium heparin tube
- Fasting: No fasting required
- Turn-around: 2-5 business days. May take longer based on weather, holiday or lab delays.
Benefits
- Monitor cardiovascular risk by measuring blood thickness that affects circulation
- Detect hyperviscosity syndromes early to prevent stroke and thrombosis complications
- Convenient assessment without specialist referral, with physician consultation available
- Track treatment progress for blood disorders, diabetes, and kidney disease
- Stable specimen allows flexible testing—sample remains viable refrigerated up to 4 days
Who Is This Test For?
- Individuals experiencing poor circulation symptoms like headaches, vision problems, or dizziness
- Patients with diagnosed blood disorders requiring viscosity monitoring
- People with diabetes, kidney disease, or cardiovascular risk factors
- Those with suspected polycythemia, multiple myeloma, or hyperviscosity syndrome
- Anyone monitoring treatment effectiveness for blood-related conditions
How It Works – Just 3 Steps
- Order online — purchase your test without a doctor's referral
- Visit a lab — get your blood drawn at a nearby location
- Receive results — typically within 2-5 business days.
FAQ
What does this test measure? Blood viscosity—the thickness and resistance of blood as it flows through vessels, measured in centipoise (University of Michigan 2025, mlabs.umich.edu).
Will dehydration affect my results? Yes, dehydration can falsely elevate viscosity readings; stay well-hydrated before testing.
Do I need to fast? No fasting is required for this test.
How are results reported? Results show plasma viscosity in centipoise and equivalent hematocrit values for clinical correlation.
What conditions cause elevated viscosity? Multiple myeloma, polycythemia, Waldenström macroglobulinemia, and certain autoimmune disorders increase blood thickness.
Can this test predict stroke risk? Elevated blood viscosity is associated with increased stroke risk and thromboembolic events (Frontiers in Neurology 2025, frontiersin.org).
More Details
What is the purpose of this test?
The Viscosity Blood Test measures how thick or viscous your blood is as it flows through vessels. Using a Brookfield cone-plate viscometer at body temperature (37°C), the test evaluates both plasma and whole blood viscosity—expressed in centipoise and hematocrit equivalents. Blood viscosity depends on hematocrit levels, plasma proteins, and blood cell characteristics. Elevated viscosity impairs circulation and oxygen delivery to vital organs, potentially signaling underlying disorders like hyperviscosity syndrome, multiple myeloma, or polycythemia (University of Michigan 2025, mlabs.umich.edu).
Who would benefit from this test?
This test helps individuals experiencing symptoms of poor circulation—including headaches, abnormal bleeding, vision problems, vertigo, chest pain, or shortness of breath. It's valuable for patients with diagnosed blood disorders requiring monitoring, those with diabetes or kidney disease affecting blood rheology, and people with cardiovascular risk factors. Children with growth concerns related to reduced organ blood flow and adults with autoimmune diseases like rheumatoid arthritis or lupus also benefit. Individuals with leukemia, lymphoma, sickle cell anemia, or Waldenström macroglobulinemia use this test to monitor hyperviscosity complications.
When should I order a Viscosity Blood Test?
Order this test when suspecting hyperviscosity syndrome based on symptoms like sudden weight loss, seizures, or unexplained bleeding. It's appropriate for monitoring known blood-related conditions, evaluating thromboembolic risk in diabetes or cardiovascular disease, and assessing treatment effectiveness for disorders affecting blood thickness. If you have abnormally high red cells, white cells, or serum proteins, or conditions producing abnormally shaped red blood cells, this test provides valuable circulation assessment.
How do I interpret the results?
Higher viscosity values indicate thicker blood that resists flow and may impair circulation. Results should be correlated with your clinical picture and other laboratory findings.
Normal range
- What it means: Blood flows appropriately through vessels
- Typical action: Maintain healthy hydration and lifestyle
Mildly elevated
- What it means: Slight increase in blood thickness
- Typical action: Monitor with repeat testing; review medications
Moderately elevated
- What it means: Impaired circulation; increased cardiovascular risk
- Typical action: Physician evaluation; investigate underlying causes
Significantly elevated
- What it means: Hyperviscosity syndrome; organ damage risk
- Typical action: Immediate medical attention; potential therapeutic intervention
Elevated blood viscosity is associated with a 30% increased risk of cardiovascular events (Nature Scientific Reports 2025, nature.com).
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
No fasting is required for this test. Stay well-hydrated before your blood draw, as dehydration can falsely elevate viscosity readings. Continue your regular medications unless your physician advises otherwise. Blood is collected in a green-top sodium heparin tube and should be refrigerated if not processed immediately. The specimen remains stable for up to 4 days when properly stored.
How often should I get tested?
Newly diagnosed hyperviscosity syndrome
- Suggested interval: Every 3–6 months initially
Stable blood disorder on treatment
- Suggested interval: Every 6–12 months
Diabetes or kidney disease monitoring
- Suggested interval: Annually or as recommended
Cardiovascular risk assessment
- Suggested interval: Every 1–2 years
Acute symptoms of poor circulation
- Suggested interval: As needed during evaluation
Why early detection matters
Early detection of elevated blood viscosity reduces complications such as stroke, thrombosis, and organ damage from impaired circulation (Frontiers in Neurology 2025, frontiersin.org). Approximately 20% of diabetic patients exhibit increased whole blood viscosity contributing to vascular complications, making monitoring especially important for this population (NCBI PMC 2025, pmc.ncbi.nlm.nih.gov). Timely identification allows intervention before serious cardiovascular events occur, improving clinical outcomes. For children, detecting hyperviscosity syndrome early prevents growth impairment by ensuring adequate blood flow to vital organs like the heart, kidneys, and brain.
Related tests you may consider
Complete Blood Count (CBC) with Differential and Platelets Blood Test – Evaluates blood cell types and levels to help diagnose health conditions and track treatment response.
Immunofixation (IFE), Serum and Protein Electrophoresis Blood Test – Used to identify monoclonal immunoglobulin gammopathies. It may also indicate conditions such as multiple myeloma or Waldenstrom’s macroglobulinemia.
Prothrombin Time (PT) w/INR Blood Test – Used to diagnose bleeding or clotting disorders and to determine if a medication that prevents blood clots is effective.
