Turnaround time in the hospital laboratory: what TAT actually measures

Turnaround time is the interval between two events in a test's life. Which two is the whole argument. Order to report, collection to report, receipt to result, and result to report are four different numbers, and a laboratory that quotes one while measuring another is not being dishonest — it usually has not been asked to be precise.

Precision matters because the interval you measure is the interval you improve. Measure receipt-to-result and you will optimise the bench, which is often not where the delay is.

Where the time usually goes

In most hospital laboratories the analytical step — the machine actually running the sample — is the fastest part. The delays cluster before and after it:

• Order to collection: the requisition exists, nobody has drawn the sample.
• Collection to receipt: the sample is drawn and sitting in a tray.
• Result to verification: the number is in, nobody has released it.
• Verification to report: the result is released, the ward has not seen it.

Three of those four are handover problems, not laboratory problems. Which is why a laboratory that improves its TAT usually does so by fixing what happens at the edges.

What the system has to record

To measure any of those intervals, each event needs a timestamp that arrives by itself. A time typed in later is a recollection.

In the laboratory module, the requisition, the sample collection, the status changes and re-tests, and the result entry are each recorded as they happen, with TAT tracked across them. Where analysers are connected through LIS integration, the result lands against the right sample without a transcription step — which removes both a delay and a class of error at once.

Making the number honest

• Define the two events, in writing, before quoting a figure.
• Measure the median and the 90th percentile, not the average — averages hide the bad days that patients remember.
• Split by test and by section; a haematology TAT and a microbiology TAT have no business being one number.
• Separate routine from urgent, or the urgent ones will be invisible in the aggregate.

Doing that generally makes the reported figure worse and the laboratory better, which is the correct direction. It is also the version an assessor can follow — see our post on what NABH and NABL ask you to produce.

The rest of the diagnostics side, including radiology reporting and scan status, is on the hospital management software page.