Stat Troponin Turnaround Time
The core laboratory's stat troponin median TAT is 68 minutes (90th percentile 94 minutes) against a 60-minute target; 52 stat troponins arrive evenly between 07:00 and 19:00. Step medians are: order to draw 12 minutes, transport 9, accession and centrifuge 6, analyzer 10, technologist review 14, and result release 2. The analyzer currently runs troponin in batches every 30 minutes, adding an average 15-minute wait; the median excluding batch wait is 53 minutes. Sixty percent of troponin results could meet auto-verification rules, reducing average review from 14 to 3 minutes for those results. Two technologists staff days; one also answers the phone. Evening shift has one technologist, and TAT rises to 88 minutes. The medical director wants 90% of troponins reported within 60 minutes.
1. Calculate the expected median TAT after (a) continuous-loading the analyzer, (b) auto-verification, and (c) both. Rank the interventions and explain which one you would implement first.
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Current median = 53 minutes of step time + 15 minutes of batch wait = 68 minutes.
- (a) Continuous loading: batch wait falls to about 2 minutes, saving 13 minutes → 55 minutes.
- (b) Auto-verification: 60% of results save 11 minutes of review each = 6.6 minutes average → 61.4 minutes.
- (c) Both: 68 − 13 − 6.6 = 48.4 minutes.
Rank: continuous loading is the only single intervention that reaches 60 minutes, and it is a process change rather than a capital purchase. Auto-verification alone does not reach target but adds margin and reduces variability. Implement continuous loading first with validation and staff training, then validate and activate auto-verification. Together they create a buffer for the 90th percentile.
2. Why can the median improve while the 90th percentile remains above target? What measures and stratification would you use to manage the tail?
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The median describes the typical patient; the 90th percentile describes the tail that includes ED draw delays, transport gaps, repeat or dilution, and batch timing. A process can improve the median while the tail persists.
Use timestamped data at each step, a run chart of median and 90th percentile, percent over 60 minutes, and stratification by shift, hour, collection location, and result type. Use control charts for order-to-draw and batch wait. If the tail is driven by order-to-draw, work with the ED; if by repeats, review the dilution protocol and analyzer flags. Report the 90th percentile, not just the average, because the clinical commitment is about the patients who wait longest.
3. Evening shift has one technologist. Propose a plan to meet the target without adding a full FTE, and state the risks.
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Options without a full FTE: stagger the second day technologist to 14:00–22:30; continuous-load the analyzer; activate auto-verification; centralize phone calls; use pneumatic tube and pre-position supplies; move non-stat work away from peak evening hours.
If evening volume exceeds one technologist's capacity, request a 0.5 FTE evening position justified by TAT and error data. Risks of single coverage: inability to leave the bench for breaks, fatigue, delayed response to critical results, and specimen errors. Mitigate with backup call, a clear escalation plan, and monitoring of TAT and errors. Do not simply tell the evening technologist to work faster; the constraint is staffing and process design.