Central Diagnostic Lab

Quality Assurance

Central Diagnostic Lab Quality Assurance

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Quality Assurance

The backbone of every hospital is the laboratory and the backbone of the laboratory is its effective Quality assurance (QA) programme. Quality Assurance (QA) is a comprehensive term, which refers to all aspects of operation, from preparation of the patient, to sample collection, sample analysis, recording of the result and its dispatch.

The stages of QA are:


    The pre-analytical system takes care of the following aspects, quality of sample collection, labelling, transport, handling and storage. For test results are, markedly influenced by these, and each one can have a major effect on the accuracy of the result, so standard protocols are laid down, for the type of specimen and the nature of the test to be carried out.

    Test ordering
    Request forms are used to place the order in the hospital information system

    Patient preparation, correct sampling time
    Written instructions are made available to physicians, nursing staff and all other persons who send specimens to the laboratory for testing on the following points.

  • Patient preparation if sample should be a fasting one or not.
  • Time of collection e.g. for hormones, glucose.
  • Volume and type of sample
  • Type and proportion of anticoagulant required
  • Need for immediate processing
  • Special instructions for tests like lactate, ammonia, and drugs.
  • Specimen collection
    Specimen collection blood is collected in vacationers, CSF, urine pleural fluid, pericardial fluid are collected in sterile containers.

    Bar-coded labels are pasted on the tube before drawing, which has the name of the patient, age, date of birth, sex, and hospital registration number. Phlebotomy equipment and procedures all are set and followed, to facilitate drawing of sample in the right manner.

    Specimen preparation
    Direct centrifugation of primary tubes thus avoiding transfer into another tube and hence avoiding many errors.

    Specimen storage
    The samples are stored in closed containers, impermeable to light, or in some cases depending on the test, are aliquated and stored at appropriate temperatures, till the analysis is done. Taking care of the pre analytical storage problem.

    As majority of the errors happen in the pre-analytical phase hence all measures are taken at every step and samples are rejected outrightly as per the rejection criteria laid down .


    The following aspects are monitored, evaluated, implemented and maintained to ensure accuracy, precision and reliability of the tests carried out. The SOPs are made accessible to all the staff members, involved in testing and written down procedures for specific tests, are available at the workbench.
    The sop is approved by the in charge and revised when necessary the methods used are those validated and accepted internationally and nationally.

    Quality of distilled water
    High quality water RO water got from the main ro plant is again made to pass through a Millipore and this water is used for analysis.

    Quality of the reagents
    Reagents supplied by the manufacturers are checked for linearity and stability and only after passing the internal quality checks are the reagents procured thus ensuring that sub standard reagents are not used for analysis.

    Specimen collection
    Specimen collection blood is collected in vacationers, CSF, urine pleural fluid, pericardial fluid are collected in sterile containers.

    Soft ware programs have been created in house to get more number of tests per ml of reagent, with out compromising on the test results thus being highly cost effective.

    All testing instruments, centrifuges, semi automated pipettes are calibrated at regular intervals, the calibrators used are traceable to national/ and international reference standards, precision is maintained through use of a suitable QC material commercially procured. Records of frequency of calibration, routine maintenance and daily calibration checks of instruments are present.

    Quality control
    Internal quality control and external quality assessments are being done. Quality Control material, is analyzed at predetermined intervals, level 1, 2, and 3 are used along with patient samples, to monitor systemic and random errors. The QC materials used are traceable to national /international certified reference material, so that accuracy of measurements is monitored. All data, relating to the laboratory internal quality control practices and performance, in external quality assessment schemes are recorded, reviewed and corrective action is implemented.

    The laboratory takes part in the external quality assurance programme conducted by CMCvellore and Biorad laboratories. Written records are available to verify the results of QC and if QC out of control corrective action is taken.

    Turnaround time
    The throughput of the machine is 600 tests /hr. The samples are processed immediately, the reports are validated continuously and released as a result, the turn around time once it reaches the lab, is on an average 90 mts. The results of analysis are made available within this period so as to be useful for patient management.


    In order to avoid transcriptional errors in the results, the instrument is interfaced to the lab information system, so that the doctors are able to directly see the values in their computers.

    All the tests are verified by the in charge, confidentiality of reports is maintained Results are reported in appropriate units and reference ranges are given, for each test, for the specific age and sex of the patient. These are based on primary reference as mentioned in the method.

    Life threatening conditions results
    Some urgent tests or results of life threatening conditions e.g. cardiac enzymes is communicated urgently by telephone, even though they have been released in the computer. The staff checks the name of the patient, the registration number and after communicating the report asks them to repeat the information given.

    Disposal of samples and related materials
    The laboratory disposes contaminated waste, such as blood, body fluids, contaminated swabs, tissue papers, pipette tips, storage vials, Needles and other sharps by disinfect ion with chemicals at the workstation using sodium hypo chlorite and the rest through, authorized waste disposal agency.

    The laboratory maintains the patient’s records in the system, wherein it is ensured that all the tests performed on a particular patient, can be got by the click on a single screen. To enable the doctor to compare the old reports with the latest one, to assess how the diseases is progressing. Phlebotomy equipment and procedures all are set and followed, to facilitate drawing of sample in the right manner.

    Ethical practices
    The laboratory maintains the highest standards of integrity, in all its operations. The laboratory maintains utmost confidentiality with regard to the findings on the specimens sent to the lab, Transparency is maintained in reporting the results to the consultants and an open invitation has been given to them to walk in any day and ask for the quality control measures taken. Any additional finding found, which will have a bearing on the patient’s treatment, or diagnosis, is reported to the physician immediately.

With the blessings of god our great mentor, our endeavor is to serve mankind, we will continue to deliver, every result an absolute correct result, year after year, making the diagnostic field a better trustworthy field, for we strongly feel a wrong report is worse then no report at all. Marching ahead to wards free health for all. Living up to the motto hands that serve are holier than the lips that pray.