Quality Control

Definitions and Explanations of Quality

In simple terms quality is defined as the comparison of what is expected and what is realized. In other words it is expectations versus fulfillment. What encompasses the soul of quality definition is that Quality is the users’ pre-determined requirement of a particular product or service.

Also, quality can be defined as an entity total characteristic that bears the ability of satisfying the needs that are stated or implied (Ridley). In addition, quality is referred as the features of a product or service that serves the intended purpose (fitness of purpose).

Quality has been depicted with the consistency that may denote provision of the same product or service over a period of time making the outcome more predictable.

There Are Three Major Components of Quality Which Include

• Quality Control (QC)

Quality Control is an on-going and systematic assessment of work. This ensures that final product fulfils the previously established tolerance limits of accuracy and precision.

This primarily involves error control in test performance and verification of test results. QC must adhere to every department procedural aspects it the sense that it must be practical, achievable and practical. There must be adequate control of all materials, equipment and procedures.  Sterility and performance tests must be carried out on the culture media. In the arena of quality assurance laboratory directors and supervisors should realize that quality control is only one facet.

Components of Quality Control Program

• Specimen Collection And Transportation

The responsibility of providing instructions for the right way of specimen collection and transportation is of the laboratory. These instructions should be availed to the clinical when collecting the specimen (Ridley). The written instructions for the collection constitute the following:

• Test purpose and limitations
• Patient selection criteria
• Timing of specimen collection (e.g, before antimicrobials administration)
• Optimal specimen collection sites
• Approved specimen collection methods
• Specimen transport time and temperature
• Specimen holding instructions if it cannot be transported immediately (e.g, hold at 4C for 24 h)
• Availability of test (on-site or sent to reference laboratory)
• Hours test performed (daily or batched)
• Turnaround time
• Result reporting procedures

The laboratory should also include the guideline statements of filling out requisition. In addition to the standard information such as the patient name, hospital and laboratory number and the attending physician, other crucial information includes if the patient is on antimicrobial therapy or not, syndrome or suspect agent and immunization history (if it applies). Criteria for unacceptable specimens should be established by the laboratory (Ridley). Some of these unacceptable specimens are;

• Unlabeled or mislabeled specimen- these specimens should be identified or recollected by the collector
• Use of improper transportation medium such as of stool for ova and parasites that may not be submitted in preservatives
• Use of improper swab such as use of wooden shaft or calcium alginate tip for viruses
• Excessive transport time
• Improper collection site for requested tests such as stool for respiratory syncytial virus
• Specimen leakage from the transport container
• Sera that are excessively hemolyzed, lipemic, or contaminated with bacteria

Even though the specimen maybe unacceptable the physician ask that to be processed anyway. And if this happens, a disclaimer must be highlighted in the final report, clearly indicating that the specimen was not collected properly and the interpretation should be cautioned.

• 2-Media:

Media for isolation of microorganism is vital to the clinical microbiology. A high level of control is practiced to reflect the high risk. In accordance with the written procedure on the basis of validation process microbiological media can be prepared. The preparation details including batch numbers of reagents should be recorded for future reference. For the purpose of traceability a unique batch number should be assigned to each batch of medium. In the process of preparation, each batch should be quarantines until it is approved for the purpose of quality control (Ridley). The process of quality control involves PH check, sterility of the medium and growth promotion assurance. For the sterility test, a sample of the prepared medium (Minimum 5% for a batch size of 100 or less) is incubated at 37°C overnight followed by room temperature for 24 hours. There is no growth that is seen. The growth promotion and indication check involves inoculation of the medium with a control organism (NCTC, ATCC or similar).These are available from the Australian Collection of Microorganisms. This organism is chosen as appropriate to the medium. A list of suggested organisms and acceptable results for the culture media that are commonly used in clinical laboratories is given in table 1.

As the characteristics of a microorganism can change over successive generations, the culture used should be of not more than 5 passages of culture from a seed stock. If a ready-to-use medium purchased from a manufacturer is certified and has a documented control over the conditions of transport, there may be no need of assurance of the challenge organisms.4 Media should also be visually checked for any abnormalities (Ridley). Some of these may include: unusual colour, precipitation or cloudiness, uneven surface, bubbles or even the incorrect volume.

• Stains, Reagent and Anti-Sera

Biological reagents have lesser stability than most pure chemical and stain. All reagents must be labeled by the contents, concentration, preparation date and expiry date or the shelf-life. If a stain or reagent is prepared from another laboratory it must be recorded by the date it was received. More to this, they must be stored according to manufacturer’s instructions and discarded when they are out of date or has visible signs of deterioration (turbidity, precipitate or discoloration). Stains expire after six months therefore it must be rotated to enable the use of the new ones. Freshly prepared reagents should be subjected to quality control before they are used. If there are stains that are of low quality and do not meet the level of quality, they should be disposed (Ridley). The working solution of strains is tested weekly and those reagents and strains that are not used frequently should be tested before use. Chemical reagents performance should be tested when new batches of media with which they are being used are tested (e.g. Kovacs reagent with indole detection medium).

Filters should be regularly checked and that the stained smears must be over 12 smears. The control seamers must be reddening before the patient seamers. Controls that are unacceptable includes the following; positive control that is not stained red, negative control remaining red after decolorization and backgrounds that are not properly decolorized (Ridley). Before reporting the patient smears ensure that any problems with control smears are resolved. Some of the problems maybe major in the sense that it may require repeating patient smears in a failed staining batch. Table 4 shows recommendations for testing a number of reagents.

Work cited

Ridley, John. Essentials of Clinical Laboratory Science: Medical Lab Technician Solutions to Enhance Your Courses! Series. Connecticut: Cengage Learning, 2010.