Clinical chemistry is the study of a wide variety of clinically important chemical parameters of blood and other specimens ranging from electrolytes to cardiac markers to tumor antigens.
While much of the analysis has been automated professional input is required for quality assurance, trouble shooting and interpretation of results for clinicians. Clinical chemistry is performed in an integrated core lab at Kingston General Hospital that also provides hematology services.
The core lab performs over 2 million tests a year. The Laboratory can be reached by calling 613-548-7806.
Cardiac Troponin T (cTnT) is performed on the Roche Modular System (E170) at KGH. This test is recommended either for confirmation of an acute coronary event (AMI, ACS) or for prognostic estimation of future coronary symptoms. As a confirmatory test, it is used in conjunction with total creatine kinase (CK) which is monitored serially over time to demonstrate a typical time profile of the acute event. Our recommendations for appropriate testing and interpretation optimize detection while minimizing redundancy.
The August 2003 Hamilton Regional Laboratory Medicine Program Newsletter provides an overview of urine drug testing.
In order to facilitate the early detection of Chronic Kidney Disease (CKD), Kingston General Hospital is providing automatic calculation of GFR whenever serum creatinine is ordered in adults (> 18 years). The MDRD (Modification of Diet in Renal Disease) formula uses serum creatinine, age and sex for an eGFR that is normalized for body size.
Diagnosis of Diabetes:
A complete protein investigation for monoclonal proteins requires both serum and a first morning urine sample. Serum protein electrophoresis (SPE) and urine immunofixation screens (U-IFS) are used for both screening and for certain patients, monitoring of monoclonal protein concentrations.
Immunofixation (IFE) confirmatory testing is performed to determine the type of heavy and light chains associated with the monoclonal protein. IFE is reflexively ordered for any suspicious SPE or UPE findings. As monoclonal proteins do not change their type over time, IFE is only required at initial diagnosis.
Monoclonal proteins are monitored by the most appropriate test for each patient based on the algorithm developed at Kingston General Hospital.
Direct quantitation of IgG, IgA, or IgM (by nephelometry) is of value only in a limited number of non-monoclonal investigations, including immunodeficiency (eg in children), IgA nephropathy, and certain GI diseases. Simultaneous quantitation of all three "QIGS" is rarely indicated.
Case files are maintained for all patients with a monoclonal protein.
This is a particular area of interest for our laboratory. We would be pleased to facilitate specific research questions or audits in this area.
Biochemical Differentiation of the Porphyrias
Porphyria Investigations may be challenging as the appropriate tests for each clinical presentation need to be determined. Repeat testing may be necessary for initially equivocal or negative results.
The December 2001 Hamilton Regional Laboratory Medicine Program Newsletter provides an overview of the potential causes for false positive and false negative hCG results.
The Hamilton Regional Laboratory Medicine Program currently uses the Abbott AXSYM total b -hCG assay for serum CG assays. It is standardized against the Third International Standard 75-537 and detects both the intact whole molecule and the free Beta subunit down to a level of 2 IU/L. The urine pregnancy test is the Abbott Test Pack Plus which detects only the intact whole molecule at a level of 25 IU/L or greater.
Kingston General Hospital Core Laboratory uses the ROCHE Modular E170 automated immunoassay instrument to measure "total" (intact and beta) serum human chorionic gonadotropin (HCG).
Urine pregnancy testing is performed with the NCS serum/urine combination test.