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At a Glance

What is OI? An umbrella term for symptoms that worsen when standing and improve when lying down. It’s a hallmark feature of ME/CFS, Long COVID, and other infection-associated chronic conditions (IACCs).

Why test? Most patients go undiagnosed too long. Testing confirms symptoms are upright-related and guides treatment, further testing, or specialist referral.

Three Common Tests

• Tilt Table Test (TTT): The “gold standard.” Comprehensive, closely supervised, useful for complex cases and research, but limited access and not always necessary for initial care.
• Active Stand Test (10-min): Simple, widely used by autonomic specialists, feasible in most clinics; may be hard for highly symptomatic patients.
• 10-Minute NASA Lean Test (passive): Practical for primary care, used by ME/CFS clinicians since the 1990s, safer and more comfortable for frail or very symptomatic patients due to wall support.

What Tests Can Do: Document abnormal HR/BP responses, confirm OI, guide initial treatment. What They Can’t Do: Definitively diagnose autonomic disorders alone — diagnosis requires applying full clinical criteria (e.g., POTS = sustained HR rise ≥30 bpm, ≥40 bpm in adolescents, plus symptoms).

Stepwise Approach

1. Take a thorough history (upright vs. supine symptoms).
2. Measure orthostatic vitals with a 10-minute stand test (active or passive).
3. Apply criteria to identify subtypes when warranted.
4. Treat findings — start with non-pharmacologic strategies (fluids, salt, compression, pacing); add medications as appropriate.
5. Refer for comprehensive autonomic testing if results are unclear or conservative care fails.

Bottom Line

Start simple, diagnose thoughtfully, and escalate when needed. BHC doesn’t favor one “right” stand test — the priority is that more patients are recognized, validated, diagnosed, and treated, with clinicians equipped with practical tools.

Orthostatic Intolerance Testing Made Clear: Tilt Table, Active Stand, and the Passive Stand 

Why there’s more than one way to spot a standing-up problem—and how to use each test wisely. 

Orthostatic intolerance (OI) is an umbrella term that means certain symptoms worsen when standing and improve when lying down. OI is a hallmark feature of several infection-associated chronic conditions (IACCs), including ME/CFS and Long COVID.  

Several simple, evidence-based tests can objectively confirm the presence of OI in a clinic (or even at home with guidance). These tests can help assign a specific OI subtype like POTS—but not always. They do confirm that OI is present, and then clinicians can interpret the findings, apply diagnostic criteria to determine the subtype if evident, and plan treatment accordingly. Bateman Horne Center (BHC) plays a key role in educating clinicians and providing evidence-based resources to improve recognition, testing, and management of OI across these conditions. 

Why test for OI? 

Because most people with OI go undiagnosed for too long, especially those with ME/CFS, Long COVID and related infection associated chronic conditions (IACCs), there is a sense of urgency. The goal of testing is to: 

1. confirm that symptoms are related to being upright 
2. analyze the blood pressure and heart rate findings to guide the next steps, which may include specific treatments, further testing, or referral to a specialist 

Three common ways to test 

1) Head-Up Tilt Table Test (TTT) 

Often called the “gold standard” of orthostatic testing, the tilt table test has the person safely secured to a table with a foot plate. The movable table then gradually elevates the head, moving the person from lying flat to a semi-standing position while beat-to-beat heart rate and blood pressure are monitored, sometimes with additional autonomic testing.  An IV catheter is typically required as well for monitoring and support. 

• Strengths:  
  • comprehensive data 
  • helpful for complex or unclear cases 
  • performed under close supervision 
  • widely used in research  
  • may be conducted for longer duration (30-45 minutes), allowing delayed abnormalities to emerge 
• Limitations:  
  • limited access 
  • not always necessary for initial clinical recognition and management of OI 
  • interpretation of results may vary by provider specialty and internal protocols  
  • not a full autonomic workup on its own but can be part of one or lead to one 

2) Active Stand Test (10-minute stand) 

The International Guidelines for the Active Stand Test dictate a 5-minute period of quiet rest in the supine position followed by measuring vital signs. Then the person stands in place, unaided (not leaning), for up to 10 minutes while heart rate and blood pressure are recorded at intervals. Standing vital signs are typically compared to supine or seated vital signs. 

• Strengths:  
  • simple 
  • used by many autonomic specialists 
  • can be done in most clinics 

• Limitations:  
  • can be challenging for very symptomatic patients to complete safely without support 
  • shorter than a full TTT and does not include a comprehensive autonomic workup 

3) 10-Minute NASA Lean Test (a standardized passive standing test) 

The 10-minute NASA Lean Test dictates a 10–15-minute period of quiet rest in the supine position while recording heart rate and blood pressure measurements. Then the person stands and gently leans back against a wall (heels 6–8 inches out) to minimize leg muscle “assist,” while heart rate and blood pressure are recorded at 1–2-minute intervals for 10 minutes. 

• Strengths:  
  • practical in primary care settings 
  • widely used by ME/CFS clinicians since the 1990s 
  • may be easier for clinical staff and safer for frail or highly symptomatic patients due to wall support and ease of assistance to the floor if needed 

• Limitations:  
  • screening and assessment tool for OI, but not a full-length TTT or autonomic workup 

Key point: Passive (lean) and active stand tests are accepted ways to identify OI in a clinic setting. They are especially useful when TTT is not readily available. 

What the tests can—and cannot—tell you 

• They can:  
  • document abnormal heart rate and/or blood pressure responses while upright 
  • document physical signs and symptoms 
  • confirm the presence of OI 
  • help clinicians decide on initial treatment and whether to pursue additional testing 

• They cannot, by themselves:  
  • definitively diagnose the details of an autonomic disorder  

Example: If a passive (lean) or active stand test shows a sustained heart rate increase of ≥30 bpm (≥40 bpm for adolescents) within 10 minutes of standing without a significant blood pressure drop—and symptoms fit—your clinician may determine that POTS criteria are met. The test provided the data; the diagnosis comes from applying the full criteria, which include symptoms and physical signs. 

Safety and access matter 

BHC’s mission includes helping practicing clinicians recognize and address OI using tools that are available now. Many patients can’t access tilt table testing easily. In these cases, a 10-minute stand test—active or passive—can be a safe, practical first step that validates symptoms and jump-starts care. For patients who are very symptomatic, the passive lean may add a margin of comfort and safety in a clinical setting.    

A sensible, stepwise approach 

1. History first. Ask about symptom patterns that occur when standing vs. lying down. 
2. Measure orthostatic vitals with a 10-minute stand test. Active or passive—choose what’s safest and most feasible in your setting. 
3. Apply criteria to subtype when indicated. If conservative treatment doesn’t help or results are unclear, consider referral for comprehensive autonomic testing (which may include TTT and other assessments). 
4. Treat what you find. Non-pharmacologic strategies (fluids, salt as appropriate, compression, pacing, physical counter-maneuvers) often come first; additional pharmacological interventions may and should be considered when applied appropriately under medical supervision. 

Frequently asked questions 

Q: Does a Stand Test diagnose POTS? 
 
A: It can, but it requires clinical interpretation by a qualified medical provider.  The passive stand and active stand tests identify OI by measuring heart rate and blood pressure while upright in combination with symptoms. POTS (or another subtype) is diagnosed by applying established clinical criteria to those measurements, including suggestive symptoms. 

Q: Why do some centers prefer the active stand test? 
 
A: The active stand test is typically performed in autonomic specialty clinics, although they are more likely to do a TTT. On the other hand, ME/CFS specialty clinics have traditionally used a passive stand test, and have encouraged a standardized approach using the 10 min NASA Lean test. Both approaches can provide the data clinicians need to identify OI and gain insight about heart rate and blood pressure changes.   

Q: If a stand test is “enough,” why do a tilt table test?

A: TTT offers more detailed, standardized data and can help in complex, equivocal, or refractory cases.  The TTT is often longer, up to 30-45 minutes, which can be helpful for delayed manifestations, and has more close, detailed monitoring. It’s also essential for certain research protocols. But it isn’t always necessary for initial recognition and management. 

Q: Is the passive stand test less accurate?

A: Both active and passive (lean) stand test approaches can accurately reveal the hallmark upright heart rate and blood pressure changes of OI.  A study in 1975 with healthy volunteers compared the passive stand test to TTT and found it to be as accurate. The passive stand test was utilized in the CDC sponsored MCAM study (Multi-site Clinical Assessment of ME/CFS) that was carried out from 2012 to 2017. In addition, the 10-min passive stand test was recommended for assessment of OI in the 2015 IOM publication recommending evidence-based clinical diagnostic criteria for ME/CFS. The choice often comes down to safety, feasibility, and clinical context. 

Bottom line 

• Start simple. A 10-minute stand test—active or passive—can confirm OI and validate patients. Sometimes POTS or orthostatic hypotension are obvious and easy to spot.  There are also rare complications, so be prepared for all possible outcomes. 
• Diagnose thoughtfully. Use the test data + clinical criteria to determine POTS or another subtype. 
• Escalate when needed. If conservative care fails or questions remain, refer for comprehensive autonomic evaluation (which may include TTT). 

At the Bateman Horne Center, we don’t insist on one “right” stand test. We care that more people with symptoms are recognized, validated, diagnosed, and treated—and that clinicians have practical tools to get there. 

For clinicians: If you’d like a short checklist for conducting a standardized passive stand test, let us know and we’ll share our template. 

For OI management resources, please reference:  
https://batemanhornecenter.org/wp-content/uploads/2024/09/Orthostatic-Intolerance-Overview-240911.pdf 

For those living with ME/CFS, Long COVID and related IACCs: If your symptoms worsen when you’re upright and improve when you lie down, talk with your clinician about a 10-minute stand test and next steps. You deserve answers—and a plan. 

Learn More  
To learn more, explore the Orthostatic Intolerance chapter in the Bateman Horne Center’s Clinical Care Guide, (see “Chapter 7: Orthostatic Intolerance and Dysautonomia) which walks clinicians through assessment methods, diagnostic criteria, and management strategies. 

Additional References 
Vernon SD, Funk S, Bateman L, Stoddard GJ, Hammer S, Sullivan K, Bell J, Abbaszadeh S, Lipkin WI, Komaroff AL. Orthostatic challenge causes distinctive symptomatic, hemodynamic and cognitive responses in Long COVID and myalgic encephalomyelitis/chronic fatigue syndrome. Front Med (Lausanne). 2022;9:917019. doi: 10.3389/fmed.2022.917019. 

Kirbiš M, Grad A, Meglič B, Bajrović FF. Comparison of active standing test, head-up tilt test and 24-h ambulatory heart rate and blood pressure monitoring in diagnosing postural tachycardia. Funct Neurol. 2013 Jan-Mar;28(1):39-45. PMID: 23731914; PMCID: PMC3812719.