essentials of specimen management in diagnostic microbiology

ESSENTIALS OF SPECIMEN MANAGEMENT IN DIAGNOSTIC

MICROBIOLOGY Dr.T.V.Rao MD

AIM OF MICROBIOLOGIC EVALUATIONS

The goal of microbiologic evaluation is to provide accurate, clinically pertinent results in a timely manner. The quality of the specimens submitted to the microbiology laboratory is critical for optimal specimen evaluation

SCIENTIFIC SPECIMEN COLLECTION FOR VALID

INTERPRETATIONValid interpretation of the results of culture can be achieved only if the specimen obtained is appropriate for processing. As a result, care must be taken to collect only those specimens that may yield pathogens, rather than colonizing flora or contaminants. Specific rules for the collection of material vary, depending upon the source of the specimen, but several general principles apply

BIOSAFETY A CONCERN IN SPECIMEN COLLECTION

Wear gloves, gowns, masks, and/or goggles, when appropriate, when collecting specimens from sterile sites. Use strict aseptic technique.

SPECIMEN MANAGEMENT A NEW CONCEPT The impact of proper specimen management

on patient care is enormous. It is the key to accurate laboratory diagnosis and confirmation, it directly affects patient care and patient outcomes, it influences therapeutic decisions, it impacts hospital infection control, and it impacts patient length of stay, hospital costs, and laboratory costs, and influences laboratory efficiency. Today it is essential the clinicians should change the attitude towards the Laboratory and to be more empowered with interaction with laboratory specialists.

COLLECT THE SPECIMENS AT OPTIMAL TIMES

Collect the specimen at optimal times (for example, early morning sputum for AFB culture).

COLLECT SUFFICIENT QUANTITY

Collect a sufficient quantity of material. Use appropriate collection devices: sterile, leak-proof specimen containers. Use appropriate transport media (anaerobe transport vials, Culturette for bacterial culture, Cary-Blair for stool culture,

DECONTAMINATE THE AREA OF SPECIMEN

COLLECTIONIf appropriate, decontaminate the skin surface. Use 70-95% alcohol (ALC) and 2% chlorhexidine or 1-2% tincture of iodine (TIO) to prepare the site. Allow a contact time of two minutes to maximize the antiseptic effect.

MINIMISE THE TRANSPORT TIME

Minimize transport time. Maintain an appropriate environment between collection of specimens and delivery to the laboratory.

CLINICIAN INTERACTION IMPROVES THE LABORATORY

PERFORMANCEToday it is essential the clinicians should change the attitude towards the Laboratory and to be more empowered with interaction with laboratory specialists.

TRY TO COLLECT THE SPECIMENS BEFORE ANTIBIOTIC

THERAPY Most Important criteria of sample collection continues to be a specimen should be collected prior to administration of antibiotics. Once antibiotics have been started, the flora changes, leading to potentially misleading culture results

COLLECTING SPECIMENS FROM CRITICAL SITES

Microbiology laboratories need precise concepts to collect the specimens and use of special skills and selective media a must for effective methods in Diagnosis

APPROPRIATE LABELLING A MUST

Specimens must be labelled accurately and completely so that interpretation of results will be reliable

Labels such as “eye” and “wound specimens” are not helpful to the interpretation of results without more specific site and clinical information (e.g., surgical site infection after laparotomy).

FOLLOW THE LABORATORY MANUALS

The microbiology laboratory policy manual should be available at all times for all medical staff to review or consult and it would be particularly helpful to encourage the nursing staff to review the specimen collection and management portion of the manual

POOR QUALITY SPECIMENS TO BE

REJECTED Specimens of poor quality must be rejected. Microbiologists should act correctly and with responsibly when they call physicians to clarify and resolve problems with specimen submissions.

DO NOT PROCESS COMMENSALS

These specimens processed and many junior staff start reporting commensals and oral flora as pathogens, equally ignorant clinician, Physicians should not demand that the laboratory report “everything that grows,” thus providing irrelevant information that could result in inaccurate diagnosis and inappropriate therapy.

DO NOT CULTURE NORMAL MICROBIOTA

Many body sites have normal microbiota 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.

SWABS ARE NOT OPTIMAL SPECIMENS FOR

PROCESSINGNever forget the swab is never optimal, the laboratory requires a true clinical 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),

HAVE TECHNICAL POLICY

The laboratory should be allowed to set technical policy; this is not the purview of the medical staff. Good communication and mutual respect will lead to collaborative policies.

APPROPRIATE MICROBIOLOGY SKILLS REDUCE SUPERBUGS

Microbiology laboratory results that are reported should be accurate, significant, and clinically relevant, do not report S. pneumonia from throat swabs, Susceptibility testing should be performed on clinically significant isolates, not on all microorganisms recovered in culture.

APPROPRIATE MICROBIOLOGY SKILLS REDUCE SUPERBUGS

I wish you refer the Peer reviewed Diagnostic Microbiology text books or else you are communicating the commensal and contaminants as pathogens and with misuse of antibiotic as it a concern in the Era of raise of SUPER BUGS.

The Programme is Created and Designed by Dr.T.V.Rao MD for Health Care Professionals in

Developing World

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