Using laboratory data to categorise CD4 laboratory turn-around-time performance across a national programme

Area of Science:

• Clinical diagnostics
• Laboratory medicine
• Public health surveillance

Background:

• The National Health Laboratory Service (NHLS) aims for a 48-hour turnaround time (TAT) for CD4 testing.
• Mean TAT is insufficient for identifying specific laboratory inefficiencies or predicting target achievement.
• Accurate performance metrics are crucial for optimizing HIV patient care.

Purpose of the Study:

• To evaluate the utility of median, 75th percentile, and percentage within target CD4 laboratory TAT data.
• To develop a method for categorizing laboratory performance based on TAT metrics.
• To identify laboratories requiring intervention for improved service delivery.

Main Methods:

• Retrospective analysis of CD4 laboratory TAT data from the 2015-2016 fiscal year.
• Assessment of TAT distribution and the percentage of samples meeting the 48-hour target.
• Utilized a scatter plot to categorize laboratories into performance quadrants based on percentage within target and 75th percentile TAT.

Main Results:

• CD4 TAT data exhibited a positive skew, with a median of 17 hours and a 75th percentile of 25 hours.
• Overall, 93.2% of CD4 samples met the <48 hour TAT target.
• Out of 52 laboratories, 48 demonstrated good performance ( >85% within target and ≤48h 75th percentile), 2 were satisfactory, and 2 were poor performers.

Conclusions:

• Laboratory TAT data can be effectively used to categorize performance.
• A quadrant-based approach for TAT analysis can pinpoint laboratories needing intervention.
• This methodology supports targeted root cause analysis and service improvement initiatives.