The Field Inventory Problem
Why medical device companies lose money, time, and visibility once inventory leaves the warehouse — and practical approaches to fixing it.
Contents
- Consignment Stock
- Trunk Stock
- Loaner Kits
- Field Transfers
- Bill-Only Automation
- The Design Principle
- The 5-Question Self-Assessment
Consignment stock
Medical device companies have solved warehouse inventory. ERPs track what’s on the shelf. WMS platforms know what’s been picked, packed, and shipped. The problem starts the moment inventory walks out the door.
Once a kit, implant, or instrument set reaches the field, whether it's consigned at a hospital, sitting in a rep's trunk, loaned for a case, or transferred between reps, most companies lose visibility entirely.
Many have tried to fix these problems. Every previous fix asked field reps to do more work. More forms, more scanning, more logging into systems that weren't built for them. The ground reality is simple: if tracking inventory is harder than not tracking it, it won't get tracked. Instead, make the right thing the easy thing.
Key Statistics
- 150 days: Average field inventory carry time
- 1–4%: Annual inventory shrinkage rate
- 48%: Of implants documented at point of use
- 45–70 days: Average DSO for medical devices
The gap
Consignment inventory lives between the manufacturer’s ERP and the hospital’s system — neither side has full visibility. Your ERP shows what was shipped, not what’s been used or what’s expired. Manufacturers carry an average of 150 days of inventory in the field. For a company with $10M in field inventory, $100K–$400K per year disappears to shrinkage alone.
How it works when it’s solved
The rep emails or texts a photo of the charge sheet — the same thing they’re already doing. AI extracts the products, lot numbers, and quantities. Inventory adjusts automatically. Billing kicks off. Replenishment triggers.
Trunk stock
Sales reps carry inventory in their car — literally in their trunk or a rolling case. They bring product to cases, use what’s needed, and return what’s left. It’s the most flexible and least visible inventory model in medical devices.
The gap
Every vehicle is a mini-warehouse with no inventory system. You can buy a field app, but if it requires reps to manually enter every item they receive and every item they use, adoption dies within weeks. The system has to build inventory for them.
20 reps each carrying $50K–$200K in trunk stock = $1M–$4M in unmanaged inventory. Stock expires in trunks because nobody catches it until the next physical count.
How it works when it’s solved
Start with what happens without the rep doing anything: when the 3PL ships inventory, they CC the system on their advance shipping notice. The system ingests the ASN, extracts lot numbers and quantities, and builds the rep’s trunk stock automatically.
Loaner kits
A manufacturer sends a kit of instruments and implants to a hospital for a specific case. The kit ships out, the surgeon uses what’s needed, and the kit ships back with (hopefully) everything accounted for.
The gap
- The handoff chain: Warehouse → carrier → hospital dock → OR → recovery area → rep → different carrier → back to warehouse.
- 35–40% of kits return with discrepancies.
A discrepant return doesn’t just cost you the missing item. It blocks the kit from the next case until reconciled, adds investigation hours, and creates sterility risk.
How it works when it’s solved
The rep is already opening and closing the kit. Snap a photo before the case, snap a photo after. The system compares the two, flags discrepancies in real time, and creates an auditable record before the kit ships back.
Field transfers
One rep needs a product or kit that another rep has. Instead of ordering from the warehouse (which takes days), they arrange a lateral transfer.
The gap
An Operations VP at a mid-size orthopedic manufacturer estimated that 10–15% of their kits don’t come from the distribution center — they come from other reps via field transfers.
How it works when it’s solved
A lightweight transfer from their phone — Rep A initiates, Rep B confirms receipt, and inventory updates in real time.
Bill-only automation
Regardless of which field inventory model a company uses, the bill-only transaction is where money gets lost.
Key Steps
- Rep records usage: Paper charge sheet (or a photo of one), sent to customer service by email or text.
- Manual data entry: Data is manually entered into the ERP — product codes, lot numbers, quantities.
- PO generation & price matching.
- Invoice creation & collection.
How it works when it’s solved
The rep emails or texts a photo of the charge sheet — or uploads it through the mobile app. From there, the system takes over: AI extracts products, lot numbers, patient info, and the facility.
The design principle
Don’t add steps. Digitize the ones that already exist.
What that looks like in practice
- Each transaction captured at the source, structured automatically, and pushed into whatever system of record the company uses.
Where a 10-person ops team actually spends their time
Today: data entry & detective work. With automation: managing the business.
The 5-question self-assessment
- Total field inventory value
- Kit return accuracy
- Case-to-invoice time
- Transfer visibility
- Manual data entry headcount
If you can’t answer the first four with confidence, or if the answer to the fifth is “more than zero,” the field inventory problem is costing you real money.