What is meant by correlation and validation of results and investigations in medical laboratory?

What is meant by correlation and validation of results and investigations in medical laboratory? 

Validation describes the process of determining an assay’s fitness that has been developed, optimized a well as standardized properly for a particular intended purpose. All lab assays must be validated for species whereby they shall be utilized. It entails estimates of analytical as well as diagnostic performance features of the given test. ¹ The validation in medical is the process of confirming whether a given test fulfils the following four criteria: The test results is validated whether it reflects the reality in the body of the patient. The test result also is validated whether it has a significant relationship with the underlying disease. ² The test result is also validated whether it provides additional information which is not available already. It is also validated whether the test is cost-effective ad whether the cost if the test is justified by its usefulness. Correlation means the significant relationship between the test results with the disease in question. ³

Planning process

Involves allocating duty to a person who undertakes the process of validation and would be responsible for the final result and making decision. The requirement of the method to be used must be defined prior to testing like limits, range of work, desirable quantity and accuracy. The document for description ought to be clear and detailed such that any trained lab technician use it.

Implementation

This involves the application of the values of the limits set in the requirement stage like accuracy, quantification and precision.  The parameters are liable to change depending on the approach used by the technician. The activities and the recorded outcomes are implemented according to date, operative and the final results.

Control

Involves verifying if the all the requirements defined in the planning process have been complied with by the operator.  After the implementation of all the undertakings, the requirements are checked and scrutinized to validate if they meet the standards. For example using control measures from time to time and check limits of the line of regression. Then include such regressions if any in the process and hence make final outcome from the test. ² The procedure is then declared if it was rightly followed to the end. Finally, an official declaration is made concerning the suitability of the method used for the purpose for which it was intended.

Errors of preanalysis

The error comes from the physician at the analytic stage. It occurs in the identification of the patient, assortment, movement and analysis preparation. These errors occur either within or without the laboratory for example misidentifying the patient. ⁴ There is a policy that ensures that a patient is identified either by use of name or date of birth or using some codes on the wristband. Also ensuring integrity of the specimen and the patient. Ensuring communication among the patient attendants in the assessment of patients.

Analytical errors

They happen during testing due to machine failures, mixing of samples and interference. Use of automation to follow up, discover and record errors during testing. The equipment to be used should be tested to ascertain if they functional. Quality of management through safety of patient in the laboratory ensuring quality key indicators in the laboratory. Also frequent staff training can help in overcoming the errors.

Post analytical errors

These errors occur after the actual testing due to poor recording, reporting, poor entry of data and poor interpretation and validation of data. Evaluating the competency of the staff as well as carrying out in-service programs for the staff.

Reference

1. Annals of Laboratory Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3255486/
2. Aziz N, Zhao Q, Bry L, Driscoll DK, Funke B, Gibson JS, Grody WW, Hegde MR, Hoeltge GA, Leonard DG, Merker JD. College of American Pathologists’ laboratory standards for next-generation sequencing clinical tests. Archives of Pathology and Laboratory Medicine. 2014 Aug 25; 139(4):481-93.
3. Hammerling JA. A review of medical errors in laboratory diagnostics and where we are today. Laboratory Medicine. 2015 Sep 18; 43(2):41-4.
4. Rehm HL, Bale SJ, Bayrak-Toydemir P, Berg JS, Brown KK, Deignan JL, Friez MJ, Funke BH, Hegde MR, Lyon E, Working Group of the American College of Medical Genetics. ACMG clinical laboratory standards for next-generation sequencing. Genetics in medicine: official journal of the American College of Medical Genetics. 2013 Sep; 15(9):733.