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Hematology

Purchasing & Inventory

In Hematology, the continuous flow of patient testing relies entirely on the availability of reagents and supplies. A stockout of lyse or diluent can halt the entire department, delaying critical care for patients. Conversely, holding too much inventory ties up cash and risks product expiration. Purchasing and Inventory Management is the delicate balancing act of ensuring the right supplies are available at the right time, in the right quantity, and at the best price

Purchasing Principles

Purchasing is not simply “shopping”; it is a regulated procurement process involving contracts, purchase orders, and vendor relationships

The Purchase Order (PO)

The PO is the official, legally binding document sent by a buyer (the laboratory) to a seller (the vendor). It authorizes the purchase

  • Purpose: It tracks spending against the budget. Before a PO is issued, the requisition is often reviewed by administration to ensure funds are available
  • Blanket PO (Standing Order): A single PO issued for a specific period (e.g., one year) or a specific dollar amount. This allows the lab to order recurring shipments of hematology reagents (e.g., “Monthly shipment of Cellpack”) without needing administrative approval for every single delivery. This streamlines workflow for high-volume consumables

Group Purchasing Organizations (GPO)

Most hospitals belong to a GPO (e.g., Vizient, Premier). A GPO aggregates the purchasing power of hundreds of hospitals to negotiate lower prices with vendors

  • Benefit: A single hospital might pay $50 for a box of gloves, but a GPO contract might lower that price to $35 because the GPO represents millions of dollars in volume
  • Compliance: Laboratories are often contractually obligated to buy “on-contract” items. This limits the manager’s ability to pick any brand they want; they must choose from the GPO’s approved vendor list

Inventory Management Methodologies

The goal of inventory control is to minimize the Total Cost of Inventory, which includes the Purchase Cost (price of the item), Ordering Cost (labor to place the order), and Holding Cost (storage space and risk of expiration)

Just-In-Time (JIT)

This is a “lean” inventory strategy where supplies are delivered immediately before they are needed

  • Concept: The lab keeps very little stock on the shelves. As soon as the last box of reagent is opened, the next shipment arrives
  • Pros: Frees up storage space (critical in cramped labs), reduces holding costs, and eliminates the risk of reagents expiring on the shelf
  • Cons: Highly risky. If there is a supply chain disruption (e.g., a snowstorm, factory strike, or backorder), the lab has no safety stock and will run out of supplies, halting patient testing

Economic Order Quantity (EOQ)

This is a calculated approach used to determine the optimal order size that minimizes total costs. It balances the cost of ordering against the cost of holding inventory

  • Concept: Ordering too frequently (small batches) increases shipping and administrative costs. Ordering too rarely (huge batches) ties up cash and clogs the refrigerator. EOQ finds the mathematical “sweet spot”
  • Formula: \(\text{EOQ} = \sqrt{\frac{2 \times \text{Annual Usage} \times \text{Ordering Cost}}{\text{Holding Cost}}}\)

Min/Max System

This is the most common manual system used in clinical laboratories

  • Min (Reorder Point): The minimum quantity of stock allowed on the shelf. When inventory drops to this level, it triggers an order. The Min level is calculated based on the “Lead Time” (how long it takes for the order to arrive) and daily usage
  • Max (Par Level): The maximum quantity of stock the shelves can hold or should hold. The order quantity is the difference between the Max and the current stock
  • Example: If Min = 5 boxes and Max = 20 boxes. When the laboratory scientist sees 5 boxes left, they order 15 boxes (to get back to 20)

Inventory Control Procedures

The daily management of physical stock ensures that the financial investment is protected and that regulatory standards are met

Stock Rotation (FIFO)

  • First-In, First-Out (FIFO): The cardinal rule of the laboratory. New stock is placed behind the old stock. The oldest stock (with the soonest expiration date) is always used first
  • Purpose: Prevents wastage due to expiration. Accreditation agencies (CAP/The Joint Commission) strictly cite labs for having expired reagents on the shelf, even if they aren’t being used

Cycle Counts (Physical Inventory)

The computer’s record of inventory often differs from reality due to theft, breakage, or failure to log items out

  • Procedure: Periodically (e.g., monthly or quarterly), staff must physically count every item on the shelf
  • Variance: The difference between the physical count and the system count. Significant variances indicate a breakdown in the inventory management process (e.g., people taking supplies without recording it)
  • Financial Reporting: At the end of the fiscal year, the value of the physical inventory is reported on the Balance Sheet as an asset. Accurate counts are essential for financial integrity

Lot Sequestration

In Hematology and Coagulation, changing reagent lot numbers requires time-consuming calibration and QC verification (Lot-to-Lot comparison)

  • Strategy: To minimize this workload, the lab manager asks the vendor to “sequester” (reserve) a large quantity of a single lot number sufficient to last 6 to 12 months
  • Benefit: The lab receives monthly shipments from this same reserved lot, eliminating the need to perform frequent crossover studies and recalibrations

Receiving & Documentation

The purchasing cycle is not complete until the item is received and inspected

  • Packing Slip Verification: The receiving laboratory scientist must verify that the items in the box match the packing slip AND the original Purchase Order. (Did we get what we paid for?)
  • Integrity Check: Items must be inspected for damage (crushed boxes, leaked bottles) and temperature integrity (did the cold-pack melt?). Damaged goods must be rejected immediately
  • Labeling: Upon receipt, every reagent box should be labeled with:
    • Date Received
    • Date Opened (when put into use)
    • Expiration Date (if the “open-vial” stability is shorter than the printed expiration date)