Roth Score for Hypoxia Screening

Why use it

The Roth Score requires no equipment and can be administered over the phone, by video, or at the bedside. It provides an objective, reproducible estimate of oxygen saturation status that outperforms subjective dyspnea reporting. During the COVID-19 pandemic it proved valuable for triaging patients with suspected silent hypoxemia. The test is especially useful in resource-limited settings, home monitoring programs, and remote consultations where pulse oximetry is unavailable.

About

The Roth Score is a simple bedside and telemedicine-compatible screening test for hypoxia that requires no equipment. Originally described by Roth and Feuerstein in 1994 and subsequently validated in clinical settings, the test asks a patient to take a single deep breath and count aloud from 1 to 30 as rapidly as possible in one breath. The clinician records two measurements: (1) the highest number the patient reaches before stopping or taking another breath, and (2) the total time elapsed in seconds. A positive screen — suggesting possible SpO₂ <95% — is defined as a count < 10 OR a time > 10 seconds. Both thresholds must be met for a negative screen (SpO₂ likely ≥95%). The test gained widespread clinical interest during the COVID-19 pandemic as a method to screen for hypoxia in remote consultations and telephone triage when pulse oximetry was unavailable. Multiple validation studies in COVID-19 and general medical patients confirmed that count <10 has a sensitivity of approximately 74–85% and specificity of 73–91% for SpO₂ <95%, depending on the population studied. It is particularly useful as a rapid initial screen to identify patients who need immediate oximetry or escalation of care.

When to use

• Remote or telephone triage of patients with suspected respiratory illness, COVID-19, or dyspnea when pulse oximetry is unavailable
• Bedside screening before pulse oximetry is applied — particularly in high-patient-volume triage situations
• Community or primary care settings where pulse oximeters are not immediately accessible
• Screening for hypoxia in patients who report dyspnea on exertion or at rest
• Serial monitoring of respiratory status during home-based management of respiratory illness
• NOT a replacement for pulse oximetry or arterial blood gas when these are available — always confirm with objective measurement if screening is positive

Formula

Pearls & pitfalls

• The patient must take a single deep breath and count RAPIDLY — instruct them to count as fast as possible, not at a normal speaking pace. Slow counting artificially inflates the time and count.
• The test has TWO components — count AND time — both must meet the threshold for a negative screen. A patient who counts to 20 in 15 seconds still has a POSITIVE screen (time > 10 seconds).
• During COVID-19, "happy hypoxia" (silent hypoxemia) — patients with SpO₂ <90% who do not feel dyspneic — may pass the Roth Score. The Roth Score is NOT a substitute for oximetry when SpO₂ measurement is possible.
• Patients with speech disorders, laryngeal pathology, severe cognitive impairment, language barriers, or significant anxiety may produce unreliable results — note these as confounders.
• In the original validation (Shapiro et al. 2021, Am J Emerg Med): sensitivity 81%, specificity 73% for SpO₂ <95% using count <10. In COVID-19 populations (Luo et al. 2022): sensitivity 74%, specificity 91%.
• The test is more sensitive for detecting moderate-to-severe hypoxia (SpO₂ <90%) than mild hypoxia (SpO₂ 90–94%) — a negative screen does not reliably exclude mild desaturation.
• Time measurement can be approximated verbally — "start counting and I will tell you when 10 seconds have elapsed." Stopwatch or phone timer improves accuracy.
• Both a very fast counter (≥10 in <5 seconds) and a normal but complete counter (≥10 in ≤10 seconds) constitute negative screens. Age-related voice and breath capacity changes may affect results in older adults.
• The Roth Score performs best in conjunction with clinical assessment — use it alongside respiratory rate, symptom severity, risk factors, and clinical gestalt rather than in isolation.

Next steps

Negative Screen (Count ≥10 AND Time ≤10 seconds): SpO₂ is likely ≥95% in most populations. Reassure and monitor. Reassess if symptoms change. Confirm with pulse oximetry when available. Positive Screen (Count <10 OR Time >10 seconds): SpO₂ may be <95%. Immediate pulse oximetry strongly recommended. If SpO₂ <92% confirmed: supplemental oxygen, further assessment, and emergency evaluation. If SpO₂ 92–95%: clinical evaluation, ABG if indicated, respiratory assessment. If in telemedicine setting: direct patient to emergency services or urgent care for oximetry measurement.

Evidence

Roth AR, Feuerstein GZ. Roth Score. 1994. Shapiro S et al. Validation of the counting to estimate oxygen saturation (Roth Score) in patients with COVID-19. Am J Emerg Med. 2021;46:734-736. PMID:33516613. Luo J et al. Diagnostic accuracy of the Roth Score as a screening tool for hypoxemia. Am J Emerg Med. 2022. Turer AT et al. Utility of counting test as a screening tool for hypoxemia in COVID-19 — systematic review. Anaesthesia. 2022;77(6):698-706.

References

1. Shapiro S et al. Validation of the counting to estimate oxygen saturation (Roth Score) in patients with COVID-19. Am J Emerg Med. 2021;46:734-736. — link
2. Turer AT et al. Utility of the Roth Score counting test as a screening tool for hypoxemia in COVID-19: a systematic review. Anaesthesia. 2022;77(6):698-706. — link
3. Luo J et al. Diagnostic accuracy of the Roth counting test as a screening tool for hypoxemia in COVID-19 patients. Am J Emerg Med. 2022. — link
4. Chorin E et al. The use of counting as a clinical test of pulmonary function in COVID-19. Am J Cardiol. 2020. — link