PeakSonic Bladder Scanners Compared: M1, M2, M4 & M5

PeakSonic bladder scanners are point-of-care ultrasound devices used to estimate urinary bladder volume and post-void residual (PVR) non-invasively. In wards, theatre recovery, urology clinics, and long-term care, bladder scanning is commonly used to support urinary retention assessment and to guide decisions about observation, voiding trials, or catheterisation when clinically appropriate.

Key Takeaways

• PeakSonic M1 is a 2D handheld bladder volume instrument with a manufacturer-stated accuracy of ±14% / ±14 mL; it is often selected for straightforward bedside screening and longer continuous scan time.

• PeakSonic M2, M4 and M5 are listed as 3D scanners and state an accuracy of ±7% / ±7 mL, with an additional 'Intelligence' mode intended to help locate the bladder during pre-scan.

• M2 is an all-in-one handheld 3D device; M4 uses a smartphone/tablet app over Wi-Fi for display and storage; M5 is a 10.1-inch workstation with an in-built printer and bladder wall thickness measurement.

• If your documentation is paper-led, M5's in-built printer is usually the simplest workflow. If you are digital-first, M4's app-based storage and wireless transfer can reduce admin steps.

• Real-world accuracy depends on technique and context (patient position, targeting, body habitus, and confounders such as ascites). Build training, repeat-scan checks, and documentation standards into your pathway.

Clinical scenarios where bladder scanning adds value

Bladder scanners are typically used as decision-support tools. They help teams quantify bladder filling without immediate catheterisation. Common scenarios include:

• Suspected urinary retention (acute or chronic) where bladder volume helps guide escalation.

• Postoperative and post-anaesthetic monitoring where PVR values support a voiding trial pathway.

• Catheter review and removal pathways, including monitoring after catheter removal.

• Continence and lower urinary tract symptom pathways where repeated bladder volumes/PVRs inform next steps.

• Patients where catheterisation is difficult or high risk, where non-invasive assessment helps avoid unnecessary attempts.

Important: specific thresholds and escalation steps vary between organisations. Your local catheter and continence pathway should define when to scan, when to repeat, and what actions follow specific results.

Read more: Types of Bladder Scanners: Handheld, Portable, and Wireless

At-a-glance: which model is usually the best fit?

Use this quick mapping to shortlist, then confirm against your local workflow, infection control policy, and governance requirements.

Best fit by setting

• High-throughput ward rounds and urology clinics with print-and-file documentation: M5

• Mixed-experience ward teams that want a single handheld 3D device: M2 (consider M2-W if computer connectivity and expanded history review are required)

• Community, multi-site services, or teams that prefer a tablet/phone display and wireless workflow: M4

• Basic bedside screening where 2D is acceptable and maximum simplicity is the priority: M1 (consider M1-W for computer connectivity and record review)

Read more: Bladder Scanners in Nursing Homes: Clinical Best Practices

What changes between M1, M2, M4 and M5?

1) 2D vs 3D bladder scanning technology

Bladder scanners estimate volume by acquiring ultrasound data from the lower abdomen and using software to calculate an approximate bladder volume. In simple terms, 2D systems rely on one or more 2D views and geometry-based estimation, while 3D systems acquire multiple slices/planes to reconstruct a 3D representation and calculate volume from that dataset. In the PeakSonic range, the M1 is listed as 2D, while M2, M4 and M5 are listed as 3D.

A tighter stated accuracy spec is one reason many services prefer 3D for structured urinary retention pathways. However, even 3D devices can be inaccurate if the probe is not centred, if the bladder is not adequately filled, or if non-bladder fluid is present. Treat the number as a decision-support input, not a diagnosis on its own.

Read more: 2D vs 3D Bladder Scanners: What’s the Difference?

2) Modes: Easy vs Expert vs Intelligence

Across the PeakSonic range, manufacturers list Easy and Expert modes on all models, with Intelligence mode listed on M2, M4 and M5 (and described in pre-scan workflow text on some pages). A practical way to think about these modes:

• Easy mode: prioritises speed for routine assessments.

• Expert mode: default mode; intended for clinicians who want more control and consistency.

• Intelligence mode: adds automated guidance/positioning support during pre-scan to help locate the bladder centre and improve targeting, which can reduce user-dependent error.

3) Workflow and display: handheld vs mobile app vs workstation

The form factor is often the biggest day-to-day difference:

• M1 and M2: all-in-one handheld units with an on-device touchscreen for scan control, patient entry, and reviewing results.

• M4: a probe that connects to a smartphone or tablet via Wi-Fi; images and volumes are displayed in an app and stored on the mobile device.

• M5: a cart/workstation approach with a 10.1-inch console display, a probe positioning guide, and an in-built printer.

Choosing the workflow is less about 'better technology' and more about what your team can sustain: mobile-device governance, where scans happen, and how results are recorded.

4) Documentation, storage and connectivity

Documentation is where many bladder scanning programmes succeed or fail. If results cannot be captured reliably, scans become hard to audit and harder to act on consistently.

• Printing: M1/M2/M4 list Bluetooth printing; M5 lists an in-built printer.

• Storage: M1 and M2 list TF card storage; M4 stores on the connected phone/tablet; M5 lists >10,000 stored cases.

• Connectivity: M1-W and M2-W add Wi-Fi-to-computer functions; M4 and M5 list USB/Wi-Fi data transfer.

Understanding the spec sheet (what each number really affects)

• Volume range (0-999 mL): rarely the limiting factor; most protocols act well below this maximum.

• Accuracy (e.g., ±7%/±7 mL vs ±14%/±14 mL): impacts confidence when thresholds trigger actions. Lower stated error is generally preferred for structured pathways.

• Probe frequency (2.5 MHz): a lower-frequency abdominal probe supports penetration; targeting and patient factors still matter more than the headline frequency.

• Continuous scanning time vs standby time: continuous time matters for long bedside rounds; standby matters for devices kept ready for ad-hoc scans.

• Battery capacity (mAh): not directly comparable without considering device design; use the published run-time figures for real-world expectations.

Detailed comparison table (specification-led)

The table below focuses on published technical specs that most often matter to procurement and daily workflow. Where a capability depends on a variant (e.g., M1-W, M2-W), that is noted in the cell.

Model-by-model: what the differences mean in practice

PeakSonic M1: 2D handheld for straightforward bedside scanning

The PeakSonic M1 is listed as a 2D handheld bladder volume instrument. It measures 0-999 mL with a 2.5 MHz probe and a touchscreen interface. Key published specs include a 2600 mAh battery, >3 h 20 min continuous scanning time, ≥5 h standby time, Bluetooth printing, TF card storage, and a stated accuracy error of ±14% / ±14 mL.

Operational strengths

• Continuous run time: often helpful for long ward rounds and multi-room scanning.

• Simple workflow: fewer moving parts (no external tablet/console) can be easier for basic deployment.

• Documentation options: Bluetooth printing plus on-device data entry (virtual keyboard or voice annotation is listed).

Variants and connectivity

The M1-W variant is listed with Wi-Fi data transfer to a computer and enhanced patient records review (listed as >1k records). If your service needs a scan history review for audit or follow-up, this variant can reduce manual steps.

Limitations to plan for

• 2D scan + wider stated error (±14%/±14 mL) can be less suitable when strict numeric thresholds drive decisions.

• Protocols should include repeat scanning when results do not fit symptoms, and clear documentation of timing for PVR.

PeakSonic M2: 3D handheld with Intelligence mode

The PeakSonic M2 is a 3D handheld bladder scanner (0-999 mL; 2.5 MHz) with Easy, Expert and Intelligence modes listed. Key published specs include a 2600 mAh battery, 2 h 30 min continuous scanning time, ≥5 h standby time, Bluetooth printing, TF card storage, and a stated accuracy error of ±7% / ±7 mL.

Why many services standardise on M2

• Handheld form factor: minimal workflow change compared with basic bladder scanners.

• 3D scanning: tighter stated accuracy spec can increase confidence in structured pathways.

• Intelligence mode and intelligent positioning are described to help locate the bladder during pre-scan, which can improve consistency for less experienced users.

• Documentation support: voice annotation and virtual keyboard entry are listed.

M2-W: what the Wi-Fi variant adds

M2-W is listed with Wi-Fi connection to a computer and expanded history review (listed as >1k records). This matters when scan records need to be reviewed, edited, or printed through PC software, or when audits require longitudinal access.

PeakSonic M4: wireless 3D scanning using a smartphone/tablet display

The PeakSonic M4 uses the same 3D scanning core (0-999 mL; 2.5 MHz; ±7% / ±7 mL stated accuracy) but changes the workflow: the probe connects to a smartphone or tablet via Wi-Fi, and images/data are displayed in an app. Published specs list a 2400 mAh battery, 2 h 20 min continuous scanning time, and >4 h 20 min standby time.

Where M4 tends to outperform handheld-only workflows

• Training and visibility: a tablet display can make image review clearer for supervision and competency checks.

• Digital documentation: app-based storage on the connected device reduces reliance on paper and can support faster reporting.

• Mobility: the probe is lightweight and a trolley workflow is described for hospital use when needed.

Governance considerations

• Mobile device management: define who can log in, where data is stored, and how long it is retained.

• Infection control: ensure cleaning SOPs cover the tablet/phone case, not just the probe.

• Connectivity: plan for Wi-Fi environments and contingencies for areas with poor signal.

PeakSonic M5: workstation-style scanning with in-built printing and wall thickness measurement

The PeakSonic M5 is positioned as a high-throughput 3D scanning workstation with a 10.1-inch TFT-LCD display and an in-built printer. Published specs list a 3200 mAh battery, 2 h continuous scanning time, >28 h standby time (screensaver status), >10,000 stored cases, USB/Wi-Fi transmission, and accuracy error of ±7% / ±7 mL. Key differentiators include bladder wall thickness measurement and dual-screen display during bladder positioning.

Read more: Understanding Bladder Volume Measurement in Clinical Practice

Why M5 is commonly chosen for high-volume pathways

• Immediate documentation: printouts can include patient details, images, and measured values without relying on Bluetooth pairing.

• Urology and complex pathways: additional features (wall thickness measurement, enhanced positioning) support advanced use cases.

• Always-ready station: long standby time supports ad-hoc scanning without worrying about daily charging cycles.

How to choose: a decision checklist for procurement

Use this checklist to align the model to your workflow and avoid surprises after purchase.

1) Accuracy and pathway design

If your protocol uses defined thresholds to trigger actions (for example, repeated PVR values driving catheter decisions), many services standardise on 3D (M2/M4/M5) because those models list ±7% / ±7 mL. If your use case is broader screening with more tolerance, M1 can still be suitable.

2) Documentation method (paper vs digital)

• Paper-first: prioritise M5 (in-built printer) or ensure Bluetooth printing is supported and reliable (M1/M2/M4).

• Digital-first: M4's app-based workflow can simplify storage and transmission; M1-W/M2-W can support computer integration where desired.

3) Deployment environment

• Bedside rounds across multiple rooms: handheld devices (M1/M2) minimise setup.

• Clinic-based scanning stations: M5 can streamline repeat workflows and documentation.

• Community and multi-site: M4's portable probe + tablet display can be efficient when governance allows.

4) Training and competency (minimum checklist)

A simple competency checklist prevents most accuracy problems:

• Indication understood: why the scan is being done and what action may follow.

• Patient prep: position, privacy, and recording the time of last void (critical for PVR).

• Probe targeting: correct anatomical landmarking and ensuring the bladder is centred in the scan.

• Repeat-scan rule: repeat if the value does not match symptoms or if targeting is uncertain.

• Documentation: record volume, timing, indication, and whether value is initial or repeat.

• Escalation: follow local pathways for when to involve senior clinical review.

5) Data and infection prevention governance

Confirm local cleaning requirements for probes, devices, carts, and mobile displays. For M4 deployments, include mobile device management, access control, and data handling rules.

Vendor questions to ask before purchase

• Which exact model and variant are we quoting (e.g., Wi-Fi 'W' variants, printer bundle, trolley)?

• What is included in onboarding, training, and competency sign-off support?

• How is data stored and exported (format, encryption at rest/in transit, user access controls)?

• What are the cleaning and disinfection recommendations for the probe and any touch screens or carts?

• What warranty, service turnaround, and loan device options are available?

Read more: How Much Does a Bladder Scanner Cost in the UK? A Buyer’s Guide

Rollout tips that improve real-world accuracy

• Define indications: when to scan, when to repeat, and when to escalate.

• Standardise timing for PVR scans (scan promptly after voiding and record times).

• Train for confounders: body habitus, bowel gas, postoperative dressings, pelvic anatomy changes, and known ascites can affect readings.

• Repeat scans when results do not fit the clinical picture; record whether the value is initial or repeat.

• Audit early: check documentation completeness and consistency of decisions against your pathway.