Department of Chemical Pathology

The Clinical Biochemistry Laboratory

The Department of Chemical Pathology is situated in the main laboratory complex of the National Hospital of Sri Lanka (NHSL) and consists of two laboratories namely Clinical Biochemistry and Immunoassay (Radioimmunoassay) laboratories. The Chemical Pathology laboratory provides comprehensive laboratory services to the patients over 24 hours, seven days a week on the basis of the tertiary referral laboratory of Sri Lanka. This is the largest medical laboratory in the government health sector, performing over 1.2 million and 0.12 million tests per annum in Clinical biochemistry and Immunoassay respectively. The laboratory provides services to, surgical wards, medical wards, other sub specialities, outpatient department and intensive care units. It supports the other hospitals island wide through a direct referral system. The funding for the reagents, chemicals; equipment and recruitment of staff is performed by the Ministry of Health, Sri Lanka in order, to deliver an efficient free health care service.  


The Clinical Biochemistry laboratory is situated in the second floor of the laboratory complex. It is functioning as one of the four main pathology laboratories since the establishment of the Department of Pathology at the NHSL. At the commencement all the investigations were based on conventional manual clinical biochemistry methods. Later, in 1990, two automated biochemistry analysers were introduced. Most of the reagents were prepared in house in cost effective manner and introduced to the analysers. Due to the increasing bed strength and the requirement of variety of investigations, three more auto analysers were introduced with traceability established commercial test kits and calibrators. In 2005, sample collection was upgraded with introduction of collection tubes instead of recycled penicillin bottles. With the introduction of primary sample tubes, ward staff was able to send one sample for multiple investigations of the same patient and it enabled to minimize some of the pre analytical errors. The autoclavable glass tubes are re-cycled following an extensive cleaning procedure.  The units of measurement on the reports were converted from conventional units to international units in 2007 and a new request form with a report format overleaf for clinical biochemistry was introduced. At present, the laboratory is equipped with one high capacity fully automated chemistry analyser and four low capacity fully automated chemistry analysers.

Laboratory Tests and technology

Clinical Chemistry laboratory performs analysis of almost all body fluids such as urine, cerebrospinal fluid (CSF), but mostly on serum and or plasma. At present, it accepts approximately 1500 patient samples for up to about 5000 different kinds of tests during the day time and nearly 500 samples for general biochemistry tests such as, serum creatinine, serum electrolytes, plasma glucose, urine full report and CSF analysis in the night. The biochemical tests are categorised in to sub specialities of general or routine chemistry and special chemistry.

The general or routine biochemistry tests include plasma glucose, blood urea, serum total cholesterol, serum creatinine, serum electrolytes, serum total bilirubin, serum direct bilirubin, serum aspartate aminotransferase, serum alanine aminotransferase, serum alkaline phosphatase, serum total protein, serum albumin, serum creatine kinase, serum amylase and therapeutic drug level of lithium level which cover cardiac, renal, liver and pancreatic disorders. Special chemistries include techniques such as, gel electrophoresis for serum and urine protein electrophoresis, ionized calcium performed by Ion Selective technique, serum and urine osmolality, pH analysis as well as serum total calcium, inorganic phosphate, iron, iron binding capacity and magnesium. The 24 hour urine analysis for creatinine, calcium, magnesium, electrolytes, uric acid and phosphorus are performed with prior arrangements with the laboratory.

The clinical biochemistry dynamic function tests such as, acid loading test, water deprivation test, glucose tolerance test and special qualitative tests such as, cryoglobulin evaluation are carried out with the supervision and instructions of the laboratory team and using recently prepared laboratory protocols according to the ISO 15189 guidelines. Urine and faecal analysis are also performed as routine clinical biochemistry including urine for Bence Jones protein and stool occult blood. C- reactive protein test was introduced recently and at present under evaluation and familiarization as a routine test. A new biochemistry request form with report format (ISO15189:2012 E 5:4:3) has already been prepared and will be introduced in the near future. As the reference laboratory these facilities are provided to any requested government hospital.

Turnaround time and Quality assurance

The tests are available 24 hours a day on a priority basis, with minimum delay following reception of patient samples at the laboratory. Urgent laboratory tests that are needed for the management of medical emergencies are given highest priority throughout the pre analytical, analytical and post analytical phases. Abnormal results and critical values are informed verbally over the phone prior to issue of reports.

Analysis of serum samples by five automated analysers reduces the turnaround time and increases efficiency of the laboratory with high precision and accuracy of the patient results. Four levels of quality control samples are analyzed on all five automated analyzers on a daily basis for validation of the precision. The purpose of these internal quality control samples is mainly to verify the acceptance or rejection of patient results. The technical validation of the quality control results are performed by the medical laboratory technologists, medical officers, biochemist and finally by the Consultant Chemical Pathologist. Quality control charts and records are maintained to carry out the trend analysis. The analytical methods are calibrated on a weekly basis on the first day of the week as well as when there is a quality control failure and at the time of change in kits and lots of reagents. Participation in two external quality assurance schemes monthly allows the laboratory to have a retrospective estimate of its performance in terms of both imprecision and inaccuracy. The ‘blind’ external quality control sample received from the Medical Research Institute, Colombo is subjected to analysis under routine conditions on all five analyzers including the analyzers used for the night laboratory service and the outpatient department. Once the performance report is received, the intra equipment evaluation is carried out to determine the laboratory position compared to the peer group of laboratories, to find the root causes of any error and to take immediate corrective actions. 

Training and research

This is the main training centre for all medical post graduate trainees in Chemical Pathology, medical students and trainee medical laboratory technologists. The laboratory provides facilities for research projects carried out by the professional staff. Internal audits on the pre analytical, analytical and post analytical phases of laboratory procedures are carried out routinely to improve the performance.

Laboratory Staff

The clinical biochemistry laboratory has academically qualified, experienced staff consisting of a Consultant Chemical Pathologist, biochemist, senior medical laboratory technologist, fifteen medical laboratory technologists and eight other support staff.

Out of hours service {night laboratory)

The night laboratory service is under the supervision of the superintendent medical laboratory technologists. The operation of the chemistry analyzers are solely carried out by the well experienced medical laboratory technologists of the clinical biochemistry laboratory on a rotational basis. The medical laboratory technologists of the other departments offer assistance for the other activities of the night laboratory. The critical values are informed to the ward staff over telephone prior to the release of reports. The documented procedure for acceptance of samples has been prepared and the implementation of the primary sample traceability with ‘handing over-taking over’’ and ‘’done- checked’’ procedure is an absolute requirement to ensure the reliability of test reports released from the night laboratory. 

Future developments 

Accreditation of the Biochemistry Laboratory

Aiming at the laboratory accreditation under ISO 15189- 2012 guide, the laboratory has commenced a phased out programme to achieve this important activity. The documentation of a quality manual, procedure manual, sample collection manual and standard operating procedures (SOPs) for all the biochemical tests is being carried out at present. In order to monitor the pre-analytical phase and avoiding the sample mix up at the sample collection point and at the laboratory, a documented procedure has been developed with emphasis on implementing the ‘handing over –taking over’’ and ‘’done- checked’’ procedures. A major commitment is required by all the staff involved in the pre-analytical phase. The laboratory information system will be introduced in the near future as this activity has been identified as a priority in the master plan for the NHSL. It will reduce the pre- analytical and post- analytical errors especially the transcription errors.

As per the requirement of quality improvement of the international standard, documentation and implementation of the maintenance procedures for the equipment available at the laboratory are being carried out by the staff with the assistance of the local agents. Calibration schedules, preventive maintenance procedures, contingency plans in the event of a breakdown are being partly implemented. A major activity that has been undertaken by the laboratory is the validation of the in- house analytical methods in comparison to the commercially available reagent kits. The extensive experimental evidence of performance characteristics  have  proved that the in-house prepared reagents are satisfactory and in fact with some analytes it is superior to the commercial reagent kits, if the analytical grade chemicals are being used in the preparation of reagents. This activity is being carried out by the experienced medical laboratory technologists, biochemist and under the direct supervision of the Chemical Pathologist. A significant cost reduction has been achieved during the purchasing of reagents.


The Clinical Pathology service will be upgraded by purchasing a polarized microscope for the accurate identification of dysmorphic red cells. A method comparison will be performed to select the best analytical method for urine and CSF protein estimation.

During the years 2014 -2015, the clinical biochemistry laboratory will be well equipped with essential laboratory equipment, funded by the Ministry of Health. A high performance fully automated open system analyser will be introduced to enhance the quality and the turnaround time of the clinical biochemistry laboratory tests with machine generated quality patient reports. A robust analyser with true open system will be purchased that can accommodate the in-house prepared reagents. A plant that generates type 2 and type 1 water to be used in the analysers and for the preparation of reagents will be installed.  As the main reference laboratory test panel will be expanded by introducing the lipid profile, HbA1C by high performance liquid chromatographic analysis and further development of serum protein electrophoresis including immune-fixation technique and nephelometric analysis for the determination of immunoglobulins.

Continuous Proficiency Development and trainingIntra

A comprehensive continuous education programme is planned for the staff of the department of Chemical Pathology as a prerequisite for the accreditation process. This will cover the core Chemical Pathology subject area, quality assurance, biosafety, waste disposal and communication skills.

Immunoassay (RIA) Laboratory


The Immunoassay laboratory (RIA laboratory) was established at the National hospital of Sri Lanka (NHSL) in 1989 as a tertiary referral laboratory. It is situated in the ground floor of the laboratory complex. The laboratory provides comprehensive laboratory services for the NHSL and forty six other government hospitals island wide. As a referral laboratory it is committed in providing free quality medical laboratory testing services for all the government hospitals and health institutions.

Laboratory tests and technology

The laboratory had been initially using in-house prepared radio immunoassay reagents for testing in cost effective manner. Currently the laboratory uses traceability established internationally accepted commercially prepared radioimmunoassay reagent kits. In addition, the modern technology of chemiluminescence immunoassay has been introduced to perform laboratory tests using fully automated analyzer and internationally accepted commercial reagents.

The laboratory performs specialized hormone assays such as Growth hormone, Cortisol, Luteinizing hormone, Follicle stimulating hormone to diagnose endocrine disorders, tumour markers such as, Cacinoembryonic antigen, Prostate specific antigen, Alpha feto-protein for the diagnosis of malignancies. Dynamic function tests such as, Insulin tolerance test, Glucagon stimulation test, overnight, low dose, prolonged dexamethasone suppression tests, short synacthen test and growth hormone levels following oral glucose tolerance test are used for the evaluation of the pituitary and adrenal glands. Tests such as, Adrenocorticotrophic hormone and Parathyroid hormone are exclusively done by the RIA laboratory for the government health sector. Sample analysis of highly specialized tests such as, inferior petrosal sinus sampling (IPSS) is also performed in collaboration with the endocrinology unit. The panel of laboratory tests has been recently expanded by introducing new tests such as, plasma aldosterone, plasma renin and urine microalbumin, some of which are very expensive and not freely available even in the private sector.

RIA laboratory also provides clinical advisory services, which includes the clinical interpretation of laboratory results, advice on appropriate selection of laboratory tests, investigation and monitoring strategies for individual patients and for specific diseases. There is close liaison with clinicians and other health care professionals within the community and other hospitals to ensure best practices in the use of the service.

Quality control procedure

Every assay is performed with the use of traceability established calibrators to generate reliable test results. The expected quality of the tests is maintained with the use of internationally accepted third party internal quality controls of low, medium and high levels. All the assays are performed by well trained medical laboratory technologists and all the results are technically and clinically validated by a laboratory panel consisting of the Consultant Chemical Pathologist, Postgraduate trainees in Chemical Pathology, medical officers, Biochemist and medical laboratory technologists.

Training and research

Apart from providing a comprehensive pathology service, the laboratory is capable of meeting the training requirements of various professionals such as, medical postgraduates, undergraduates and trainees in medical laboratory technology in the health sector. The laboratory also provides facilities for devising and conducting basic and applied research for the development of laboratory practice in chemical pathology.

Laboratory Staff

The Immunoassay laboratory has qualified, experienced staff consisting of a Consultant chemical pathologist, Biochemist, senior medical laboratory technologist, six medical laboratory technologists and five other support staff.

Future developments

Accreditation of the Immunoassay Laboratory

The process of laboratory accreditation to fulfill the requirements of the ISO- 15189- 2012 has been commenced with the improvements of quality system. The guidelines for sample acceptance from the National hospital as well as from out station hospitals have been prepared. The establishment of the primary sample traceability will be implemented through the “handing over –taking over’’ and ‘’done- checked’’ procedures. An inter-laboratory comparison for hormones and tumour markers is a major requirement for accreditation.

Establishment of new tests

The Immunoassay laboratory will be equipped with latest immunoassay technology by purchasing a fully automated chemiluminescence immunoassay analyser to provide an efficient service for the government health sector. Tests such as, 25 – OH vitamin D, serum IGF-1, estradiol and total testosterone are to be established in the near future. The laboratory has also planned to establish a comprehensive therapeutic drug monitoring system as a future development to fulfill the requirement of drug analysis.

Continuous proficiency development

An annual training plan is designed to improve the theoretical and practical knowledge of all the members of  staff of the laboratory.

FaLang translation system by Faboba