Question

Know how blood and lab specimens should be handled after collection

Answer 1

Handling of Specimen Management

It is important to be knowledgeable of caveats that are relevant to specific specimens and diagnostic protocols for infectious disease diagnosis. However, there are some strategic tenets of specimen management and testing in microbiology that stand as community standards of care and that set microbiology apart from other laboratory departments such as chemistry or hematology. Ten points of importance are:

The laboratory should set technical policy; this is not the purview of the medical staff. Good communication and mutual respect will lead to collaborative policies.
The laboratory must follow its procedure manual.
A specimen should be collected prior to administration of antibiotics. Once antibiotics have been started, the microflora change, leading to potentially misleading culture results.
Specimens must be labeled accurately and completely so that interpretation of results will be reliable. Labels such as “eye” and “wound” are not helpful to the interpretation of results without more specific site and clinical information (eg, dog bite wound right forefinger).
Microbiology specimens should be delivered to the testing laboratory without delay, and according to the lab’s requirements for specimen transport and stability.
“Background noise” must be avoided where possible. Many body sites have normal flora that can easily contaminate the specimen. Therefore, specimens from sites such as lower respiratory tract (sputum), nasal sinuses, superficial wounds, fistulae, and others require care in collection.
The laboratory requires a specimen, not a swab of a specimen. Actual tissue, aspirates, and fluids are always specimens of choice, especially from surgery. A swab is not the specimen of choice for many specimens because swabs pick up extraneous microbes, hold extremely small volumes of the specimen (0.05 mL), make it difficult to get bacteria or fungi away from the swab fibers and onto media, and the inoculum from the swab is often not uniform across several different agar plates. Swabs are expected from nasopharyngeal and viral respiratory infections
Specimens of poor quality must be rejected. Microbiologists act correctly and responsibly when they call physicians to clarify and resolve problems with specimen submissions.
Physicians should not demand that the laboratory report “everything that grows,” thus providing irrelevant information that could result in inaccurate diagnosis and inappropriate therapy.
Susceptibility testing should be performed on clinically significant isolates, not on all microorganisms recovered in culture.
Microbiology laboratory results that are reported should be accurate, significant, and clinically relevant.
The microbiology laboratory policy manual should be available at all times for all medical staff to review or consult. It would be particularly helpful to encourage the nursing staff to review the specimen collection and management portion of the manual. This can facilitate collaboration between the laboratory, with the microbiology expertise, and the specimen collection personnel, who may know little about microbiology or what the laboratory needs in order to establish or confirm a diagnosis.

Most infectious disease protocols have based their strategies on the management of results generated by microbiology laboratories. Getting the right diagnosis is contingent upon laboratory results that are accurate and clinically relevant.