CDST_LT: Quality assurance of TB Culture & DST laboratories

Quality Assurance (QA) is important to ensure quality DST results from a Culture and DST laboratory.

Foremost, it is essential to develop a Quality Assurance Plan​ that is practical and meets the laboratory requirements. It is important to ensure that specific procedures are available for specific components of the plan. ​ 

The QA plan should address the following:
1. General ​Laboratory​ Systems​
2. Examination Phase of Testing (analytical)
3. Pre-Examination Phase of Testing (pre-analytical).
4. Post- Examination Phase of Testing (post-analytical)
 

With regards to QA, it is essential that the plan is designed to improve the following: ​
 

• Reliability
• Efficiency​
• Use​ of laboratory services in order to achieve the required​ technical quality in laboratory diagnosis.
• Continuously improve the reliability and efficiency of laboratory services
• Includes quality control, external quality assessment, and quality improvement​

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Quality Control in Laboratory Arrangement and Administration 

Laboratory Arrangement​

• The laboratory should be arranged in a configuration which segregates clean areas from the dirtiest areas of the laboratory. ​
• Work areas, equipment and supplies must be arranged for logical and efficient workflow. ​
• Restricted access to containment areas; ensure that the doors are always closed during the work. ​
• Work areas should be clean, and work surfaces should be swabbed after each use with an appropriate disinfectant.   ​

Laboratory Management​ And​ Administration​
 

• Written procedures are maintained for easy reference.
• Quality control procedures must be implemented.
• Quality Control data must be reviewed at regular intervals. ​
• Records and registers​ must be maintained.
• Management of procurements: ​Equipment/ Consumables acceptance
• Tests and services must be scheduled.
• Proper management of biomedical waste must be done.

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The pre-Examination Procedure for Quality Assurance of TB and DST Laboratories includes the following aspects during post-analytical aspects:

1. Giving proper instructions to collect and transport good quality specimens:
 Appropriate specimens​
 Collection, transportation procedures​

2. Specimen monitoring requirements​:
 Documentation of specimen quality​
 Specimen rejection policy​

3. Test requests​:
 Essential documentation (patient name, specimen source, diagnostic and/ or follow-up, collection date) ​
 Compared to the specimen for consistency​

Resource

The examination procedure for Quality Assurance of TB and DST Laboratories includes:

1. Standard Operating Procedures (SOP)​
 Updated annually or more often as needed
 Reviewed and initiated by staff annually​
 Obsolete procedures removed, labelled as “Obsolete”

2. Calibration/ Validation- Equipment​
 Biosafety cabinets
 Safety centrifuges and autoclaves
 Thermometers, pipettes and timers​

3. Validation of new methods/procedures​
All new methods are evaluated against the reference/gold standard for​:
 Sensitivity
 Specificity​
 Positive predictive value
 Negative predictive value
 Turn-around time ​

Resource

Post-examination QA Procedures in C&DST Laboratories

Post-examination (also post-analytical phase) is one of the three-phase frameworks for the total testing process to describe issues related to the quality of laboratory testing. Most common laboratory errors occur following the testing of the sample, and some of these may be more difficult to detect. Common examples of these errors include making a transcription error when preparing the report; sending the report to the wrong location, which often results in complete loss of the report; failing to send the report.

All the C&DST laboratories should have procedures in place to ensure the validation of post-examination processes in the laboratory. These include:

• Validation of the results: In this procedure, a review is done to verify that all the data and results in the Result Report have correctly been transcribed from the Request Form, the work forms, and the register. It must also be verified that results are legible and that quality controls were correctly performed on the day the results were produced (to determine if the examinations were performed correctly and that reagents and equipment were performing correctly). The person authorized to perform this procedure must be somebody in a management position (either the head of the data management section, the head of the section where the testing was performed or the laboratory manager him/herself).

• Delivery of reports: All the C&DST laboratories should have a written protocol for sending the Result Reports to the requesters. There are two important requirements for choosing a method of sending the results: the method of sending Result Reports must have a minimal risk of losing Result Reports, and the Result Reports must always be transmitted promptly. Under NTEP, all C&DST laboratories should use the web-based portal- Ni-kshay- to send test reports. However, an alternative method should also be kept as a backup in case Ni-kshay does not work. In addition, all the C&DST laboratories should write a detailed SOP for the same. 

• Turn-around-Time (TAT): NTEP has already defined the TAT for all the diagnostics tests. The C&DST laboratory should be able to complete the test requested and report the results in Ni-kshay within the defined TAT. Period reviews should be done to ensure that the results are reported within the permissible TAT. The person authorized to perform this procedure must be somebody in a management position.

• Result audit: Periodic internal audits should be done by the C&DST laboratory on the results reported. These audits should include the entire pathway of the laboratory activities, from validating results to reporting the results in Ni-kshay.

Resource

Laboratory quality management system: Handbook. World Health Organization

Assessment

Quality Improvement Activities in C&DST Laboratories

Continuous Quality Improvement is defined as “a philosophy and attitude for analyzing capabilities and processes and improving them repeatedly to achieve the objective of customer satisfaction”. Quality improvement (QI) is a critical and often neglected part of the quality assurance process. The QI cycle involves four steps: Plan, Do, Check, and Act.

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Key Components of the QI Process:

Identification of non-conformities through data collection, subsequent data analysis, and creative problem-solving are key components of the QI process. This involves continual monitoring and identifying and analyzing actual and potential defects.

Identification of non-conformities:

Non-conformities may be identified in many ways, including Proficiency Testing (PT), reviewing quality indicators, reporting issues identified by staff members, and audits.

• Proficiency Testing: PT verifies that the C&DST laboratories are proficient in their testing process and can obtain accurate and reliable results. All the C&DST laboratories under NTEP receive an annual panel of 20 culture isolates from their respective National Reference laboratories (NRLs). PT helps to identify major non-conformities, allowing NRLs to target the most poorly performing C&DST laboratories for on-site supervision. PT panels may also be used to evaluate the training needs of technicians.

• Reviewing quality indicators: All C&DST laboratories should collect and analyze testing data on at least a monthly basis, using a standardized format. Targets should be set for all indicators monitored, and any unexplained change in quality indicators, such as an increase in error rates and contamination rates, a change in MTB positivity rate or rifampicin resistance rate, or a significant change in the volume of tests conducted, should be documented and investigated. Quality performance indicators should be reviewed by the laboratory manager and must always be linked to corrective actions if any unexpected results or trends are observed.

• Audit: An assessment, or audit, allows the laboratory to understand its performance when compared to a benchmark or standard. There are two types of audits- external and internal audits. 

  Audits should include the evaluation of steps in the whole laboratory path of workflow. They should be able to detect problems throughout the entire process. The value of a well-designed audit is that it will reveal weaknesses in the pre-examination, examination, and post-examination phases. During audits, information is gathered about: processes and operating procedures, staff competence and training, equipment, environment, handling of samples, quality control and verification of results, recording practices, and reporting practices.

Procedures for identifying non-conformities, determining responsibility, recalling the results associated with the non-conformities, and resuming routine testing following corrective actions must be clearly defined by all the C&DST laboratories. In addition, follow-up actions must also be implemented to prevent the same non-conformity from occurring in the future.

Resources

GLI Practical Guide to TB Laboratory Strengthening

Assessment

External Quality Assurance for C&DST laboratories

External Quality Assurance (EQA) is a critical component of laboratory testing, as it ensures the accuracy and consistency of laboratory test processes throughout the examination of the specimen – from the point of collection to result reporting and database entry. The EQA of the C&DST laboratory under NTEP is through structured On-Site Evaluation (OSE), panel testing and retesting exercise.

On-Site Evaluation

A field visit is an ideal way to obtain a realistic assessment of the conditions and skills practised in the laboratory. On-site evaluation of C&DST Laboratory is therefore an essential component of a meaningful Quality Assurance (QA) programme. The visit includes a comprehensive assessment of laboratory safety, including infection control measures, conditions of equipment, adequacy of supplies, as well as the technical components of culture and DST. All the C&DST laboratories are visited at least once a year by their respective NRLs for this activity. A standard comprehensive checklist for on-site evaluation of the C&DST laboratory is available. Any significant problems identified are documented in the final report.

Panel testing: 

The National reference laboratory (NRL) sends a panel of 20 strains to the C&DST laboratory every year. This panel consists of known pan-sensitive, mono-resistant, Multi-drug resistant (MDR) and poly-resistant strains and some isolates in duplicate to check for reproducibility. The C&DST laboratory sub-culture these 20 strains and then set up Drug Susceptibility Testing (DST). The results of DST are then communicated back to the NRL. The NRL checks for concordance between the results of the C&DST laboratory and their own results. The acceptable concordance level as per the NTEP guideline, is >90%. 

Retesting:

10 randomly selected recent cultures with known sensitivity patterns from a C&DST laboratory are retested at the NRL. The results are then checked for concordance. This is generally a one-time activity conducted at the time of accreditation of the C&CST laboratory. 

Resources

1. Mycobacteriology Laboratory Manual

2. Revised National TB Control Programme Training Manual for Mycobacterium tuberculosis Culture & Drug susceptibility testing. Central TB Division, Ministry of Health and Family Welfare, GOI

Assessment