Lab Turnaround Time: Benchmarks and Ways to Improve

Lab turnaround time can look healthy on a dashboard while your client services team still fields calls about missing results. A median of 45 minutes says little about the orders that wait several hours or the reports that never reach the intended destination.

The delay may sit in transport, an intake hold, a review queue, or a failed interface message. Each needs a different fix. A useful TAT review shows where orders wait, which team owns the next step, and whether a change reduces that wait.

What is lab turnaround time?

Laboratory turnaround time (TAT) measures the interval between two defined events in the testing process. A common internal measure runs from specimen receipt to result release.

Other measures start at order submission or specimen collection, or end when the receiving system accepts the report. Each answers a different operational question.

• Order submission to collection: Captures scheduling and collection delays.
• Collection to laboratory receipt: Captures pickup, transport, and receiving time.
• Laboratory receipt to result release: Covers preparation, testing, verification, and release.
• Result release to confirmed system delivery: Measures the interval between release and the receiving system's delivery confirmation.

A result in a receiving system does not prove that a clinician has reviewed it. Keep delivery, clinical acknowledgment, and follow-up measures separate.

Whenever you report TAT, name the start event and end event beside the number. This makes comparisons useful and prevents disagreements about what “on time” means.

How to Calculate Turnaround Time in a Laboratory

The basic formula is:

Turnaround time = end timestamp - start timestamp

For receipt-to-release TAT, subtract the specimen receipt timestamp from the result release timestamp.

Consider a hypothetical specimen collected at 8:00 a.m. It reaches the laboratory at 10:00 a.m., analysis finishes at 10:35 a.m., and the lab releases the result at 11:00 a.m. The receiving system confirms delivery at 11:10 a.m.

Hypothetical example. Event spacing is schematic, not proportional to elapsed time.

The laboratory's receipt-to-release TAT is 60 minutes. Collection-to-release time is 3 hours, and release-to-delivery time is 10 minutes.

Those intervals point to different investigations. If clients complain about the three-hour wait, your team needs to examine transport as well as internal processing.

Choose consistent timestamps

Before you calculate performance across a group of tests, agree on these rules:

• Receipt: Specify whether the timestamp records physical arrival or accession entry. Late registration can hide time already spent in the lab.
• Completion: Choose verification, release, or successful transmission as the endpoint.
• Time basis: State whether the target uses elapsed hours, business hours, or scheduled testing days.
• Reporting unit: Define each record as an individual test, a panel, or an entire order.
• Exceptions: Set rules for repeats, recollections, cancellations, and missing timestamps.

An order containing several tests may remain incomplete after most results become available. Track individual-test TAT and complete-order TAT separately when both matter to clients.

Record amendments separately, too. A corrected report should remain traceable without silently replacing the original release event.

Track typical performance and late results

Track typical completion times, target compliance, and unfinished work together:

• Median TAT: The midpoint of completion times.
• 90th percentile TAT: The time by which approximately 90% of measured cases finish.
• Percentage within target: How often completed cases meet the agreed service target.
• Age of open cases: How long unfinished cases have waited.
• Overdue open cases: The number of unfinished cases already beyond their target.

Calculate target compliance as:

On-time percentage = completed eligible cases within target ÷ all completed eligible cases × 100

Define eligibility in advance. Report exclusions and records with missing timestamps rather than quietly dropping them.

Two laboratories can both report a median TAT of 45 minutes while delivering very different service. In a hypothetical comparison, Lab A completes 95% of cases within a 60-minute target, while Lab B completes 75%. The median alone hides that gap.

Also review unfinished cases. A completed-case report can look better simply because the most delayed orders have not finished yet.

Lab turnaround time benchmarks and their limits

A useful benchmark needs a defined test group, clinical setting, timing interval, and measurement method. A hospital's urgent chemistry target cannot automatically serve as a reference laboratory's send-out commitment.

A UK national turnaround time survey, published in the January 2017 issue of Annals of Clinical Biochemistry, offers historical context for core investigations. A 2022 outpatient chemistry study illustrates a different, locally defined service goal.

The UK survey collected responses from 100 heads of biochemistry departments. Its figures describe professional opinion, rather than measured national performance or current US requirements.

The outpatient study used a different starting point and a specific same-day service model. Its 60-minute goal therefore cannot be compared directly with a receipt-to-report target.

Set a target that matches your service

WHO's laboratory quality implementation resource recommends examination-specific maximum turnaround times, discussion with clients, and review of the time required at each process step.

For your own target, document:

• The test or panel and patient setting.
• Routine or urgent priority.
• Start event, end event, and time basis.
• The percentage of cases expected to meet the target.
• Collection cutoffs, batch schedules, and send-out arrangements.
• Escalation responsibilities when a delay occurs.

For send-outs, check the performing laboratory's current test-specific schedule. Keep your own transport and return-delivery intervals visible.

A benchmark supports a service decision. It does not replace an agreed, clearly defined service commitment.

Find the handoffs that delay results

Start with late cases and trace the handoffs. A broad label such as “pre-analytical delay” gives a team too little information to act.

Group delayed cases by the point where work stopped. Assign each group to the team that can resolve it:

• Before processing: Client services or accessioning can review missing information, contact attempts, and resolution times. Repeated clarification requests often point to an intake problem.
• Before laboratory receipt: Logistics can compare collection, pickup, and arrival times against cutoffs. A specimen that misses a scheduled run may wait far longer than the transport delay itself.
• Before analysis: Section supervisors can compare receipt, preparation, and analyzer queue times. Arrival peaks, batch schedules, and instrument availability need separate review.
• After analysis: The authorized review team can inspect verification queues and reviewer coverage. A completed assay may still wait through a shift handover.
• After release: Interface support or IT can inspect failures, retries, and receiving-system responses. An LIS release timestamp alone cannot establish delivery.

Investigate the frequency and duration of each problem. A recurring short delay may affect more orders than an occasional long one. Clinical urgency must also guide the priority.

How to improve turnaround time in your lab

Choose an intervention that addresses the delay your data identifies. Assign an owner and decide how you will evaluate the change before implementation.

Reduce order clarification at intake

Review which lab requisition errors cause staff to contact ordering providers. Separate issues that prevent safe processing from documentation work that can follow another approved workflow.

Then place appropriate checks earlier in the process. Depending on the test, these may include specimen details, collection information, provider information, or required clinical context.

Digital lab requisitions can support this step. Docus provides configurable forms and validation checks for missing or inconsistent information before submission. Providers retain responsibility for clinical decisions and the information they submit.

Measure clarification frequency and time to resolution after the change. A faster form offers limited benefit if staff still need repeated calls to complete the order.

Match preparation and testing capacity to arrival peaks

Review workload by arrival period, location, and test group. Daily totals can conceal a short window when specimens arrive faster than staff and equipment can process them.

Check preparation queues, batch timing, staffing overlaps, and instrument availability before adding capacity.

The 2022 outpatient study illustrates this point. Researchers found that an additional analyzer alone produced less improvement than expected. A real-time monitoring approach helped route delayed specimens according to workload. Across the evaluated interventions, the share meeting the target rose from 78.5% to 88.7%.

That result belongs to one laboratory's workflow. The practical lesson is to test whether queue management, equipment capacity, or both constrain your service.

Review verification and report delivery separately

When analysis finishes promptly but release takes longer, examine why results enter manual review and how long they remain there.

Look for unclear ownership, shift handover gaps, or queues that mix urgent exceptions with routine work. Any change to verification rules needs appropriate validation and clinical oversight.

After release, inspect delivery independently. A release event in the LIS does not confirm successful transmission to every destination. For pathology services, this distinction also matters when evaluating pathology reporting software: sign-out, delivery, amendments, and audit history each need traceable events.

Check failed messages, retry behavior, destination details, and available receiving-system acknowledgments. Where electronic confirmation is unavailable, define another way to investigate delivery failures.

Keep required critical-result communication procedures visible alongside these measures. Routine report transmission does not establish that a recipient has acknowledged an urgent result.

Give each delay an escalation path

An alert needs an owner, a response, and a backup contact. Otherwise, it adds another queue for staff to monitor.

Set escalation points according to clinical need, the agreed target, and the time staff need to intervene. Record the cause, action, and resolution.

WHO's implementation resource also calls for notifying the requester of delays when an examination exceeds its TAT and the delay could compromise patient care.

Check quality and workload after the change

Compare the same test groups, priorities, and timing definitions before and after implementation. Include representative busy periods and out-of-hours work where relevant.

Alongside TAT, review:

• Corrected reports and relevant quality incidents.
• Recollections and specimen rejections.
• Manual review and repeat-testing workload.
• Overtime and result-status inquiries.
• The number and age of overdue open cases.

These checks help your team see whether the change improves the overall service or shifts work into another queue.

A practical turnaround time audit for your team

Start with one test group where missed expectations create repeated work or client complaints.

1. Define the service. Record the test group, priority, timing endpoints, time basis, and target.
2. Check the data. Inspect missing timestamps, inconsistent event order, time zones, and delayed registration.
3. Build the baseline. Calculate the median, 90th percentile, and on-time percentage. Review open cases separately.
4. Trace delayed cases. Compare their handoffs with on-time cases. Include different shifts and collection sites.
5. Select one change. Assign an owner, an expected outcome, and quality measures.
6. Review the result. Use consistent definitions and comparable workload. Document whether the change helped and what still needs attention.

Link each overdue case to its current stage, responsible team, and next action. That turns the audit into a working tool for the laboratory.

The next investment should follow the evidence. If orders wait for clarification, improve intake. If completed tests wait for review, address that queue. If released reports fail to arrive, investigate delivery. Each finding gives your team a specific place to act.