Diagnostic Testing In Laboratory

The following are the basic procedures involved in diagnostic testing in clinical chemistry laboratory.

1.  Sample Collection

The samples that are used for analysis are Serum, Plasma and Urine.

2.  Sample Analysis

The serum, plasma or urine could be analyzed for the amount of individual analytes using the appropriate enzymatic/non-enzymatic reagents.  

3.  Reporting

The results obtained are typed in a paper and the normal values established for the population is given with the results.  The normal values used to be different for Men, Women, Children and Infants.

The most commonly encountered terms in the field of clinicla chemistry are:
a. Calibration: The procedure by which, a factor is derived for the estimation of analytes in test samples, employing the absorbance of a serum/aqueous with a known value for the particular analyte.
b.  Accuracy: The ability to obtain the target value for a particular analyte, using the reagents.
c.  Precision: The ability to obtain a specified target value for a particular analyte, as close to the target as possible, when it is repeatedly tested many times, say, about 15-20 times.
d.  Cotrol :  The known sample (for which the values are pre determined by particular techniques) which have been tested and estimated for the quantity of simple analytes and complex enzymes, both in normal and abnormal ranges.

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