Transport media have long been used to maintain the integrity of clinical samples during storage and transportation to the laboratory. But is dry shipping an alternative for certain types of samples? A recent study found that self-sampling** swabs can be accurately detected after dry shipping, challenging the traditional view of appropriate shipping conditions. This raises the question: when is the transport medium necessary for a reliable diagnosis?
Can we ship samples without shipping media?
Traditionally, clinical specimens, such as swabs, need to be placed in a transport medium during their delivery to the laboratory. The transport media helps maintain the integrity and viability of the sample for accurate detection. However, a study evaluating dry and wet swabs for STD testing found that the PCR accuracy of dry and wet swabs in standard liquid transport media was similar. This indicates that a dry swab can be used in some cases.
What was tested with dry and wet swabs?
The study evaluated 793 women's self-taken ** swabs for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae using PCR. One swab from each woman is placed in the specimen transport medium (wet) and the other swab is sent dry. PCR for both swab types is comparable in detecting infection compared to traditional clinical methods such as culture and EIA. The sensitivity and specificity of the dry swab were 88., respectively9%-96.3% and 913%-99.3%。
Can we extend dry swab transport to other samples?
While the results are promising, further research is needed before dry transfer can be universally applied. Factors such as temperature stability and transit time need to be investigated for different types of samples. Self-taken swabs may be dry resistant, but other samples such as blood or sputum may be worse. However, for remote areas that lack transportation infrastructure, mailing dry samples may facilitate testing.
Are there any other advantages to transport media?
Transport media have many advantages, such as maintaining cell viability, preventing overgrowth of competing microorganisms, stabilizing certain volatile biomarkers, etc. They optimize the cells in the specimen**. While diagnosis by dry swab may seem feasible, the use of culture media may provide greater flexibility for future testing as new biomarkers become available. However, the lack of cold chain transportation may hinder testing in remote areas.
Should all laboratories switch to dry swabs?
Currently, more extensive validation is needed before a complete change in sample processing procedures can be made. Each laboratory needs to evaluate dry shipping to determine its feasibility based on its specific testing items, sample type, and shipping conditions. In places where transportation infrastructure is lacking and access to samples is limited, alternative methods such as dry mailing can help expand testing coverage. However, if there is a shipping medium, it still contributes to ideal sample preservation.
Summary
While dry shipping shows early promise in some applications, such as self-collected swabs, traditional media may still be beneficial for some samples. More research could identify areas where dry methods can complement existing approaches to improve access and diagnosis. However, the transfer medium remains an important tool for optimizing sample integrity.