A central TB diagnostic lab

I spent the past two days on a computer at the National Health Laboratory Service�s TB lab in Cape Town, finding codes and dates needed to link sputum samples to clinical data for a cohort I�m studying of MDR TB patients from a nearby farming region.  The South African government somehow has decided to keep this NHLS facility occupying prime downtown real estate � next door is historic Somerset hospital, and over lunch, I walked a couple of blocks to the high-end waterfront shopping mall � but inside, it�s a giant sample-processing factory.  Assembly lines of slides and stains and culture bottles, overflowing boxes of discarded samples making room for a new day�s sputa, a room of Bactec machines, new machines for rapid drug sensitivity testing, all kept running from early morning to 11pm, with two shifts of workers each day.  I made the mistake of trying to look up a sample by date, not realizing that a new one is logged about every two minutes.  And repetition makes the work efficient; this may seem silly, but I was amazed by how quickly the woman working next to me could stack up a tabletop array of glass slides that were lying side by side (15 or 20 per second, maybe? I�m not exaggerating - it was impressive.)

The high volume and necessarily rapid turnover mean it�s impossible to go back and find mycobacterial samples of interest after the fact.  But fortunately, our collaborators at Stellenbosch University have set up a system where all multidrug resistant samples automatically get sent to them for cataloguing, storage, and further typing and molecular analysis.  I�m eager to link their molecular data with the clinical data we�ve collected these past few weeks and see what we find.  Also curious to see whether we can show any effect from the recent implementation of rapid PCR diagnostics: Shorter times to reporting MDR TB? Shorter times to getting patients on appropriate treatment? Or, a longer shot but the real interesting question, less transmission in the community?


Emily Kendall, MGH, PGY-2 Internal Medicine