Roche CA2 Gen.2 is an in vitro diagnostic reagent for quantitative measurement of calcium in human serum, plasma and urine on cobas c systems.
What a calcium test shows
A calcium test measures the amount of calcium in the blood. A low or high level can be a sign of various conditions such as bone, thyroid, parathyroid and kidney disease. According to MedlinePlus, about 1 percent of the body’s calcium is in the blood; the rest is in the bones and teeth. For nerves, muscles and the heart to work properly, the blood level must stay within a narrow range.
Total and ionized calcium
Part of the calcium in the blood is bound to proteins and part is free. The free portion is called ionized calcium. Normally the two are present in roughly equal amounts. The total calcium test measures both together; it is the most commonly performed calcium test and is usually part of the basic or comprehensive metabolic panel. Ionized calcium is a separate measurement. According to MedlinePlus, because it is harder to perform, it is mostly requested when the total calcium result is not normal, when a condition disturbs the balance of bound and free calcium, in critically ill patients or during surgery. For example, according to OPTI Medical, the CCA-TS2 blood gas analyzer lists ionized calcium among its measured parameters; the Medica EasyStat measures calcium together with pH and electrolytes.
The Roche CA2 Gen.2 method
According to the 510(k) summary published by the FDA, Calcium Gen.2 is a photometric method defined for the quantitative determination of calcium in human serum, plasma and urine on cobas c systems. The reagent consists of two components: R1 contains CAPSO buffer and NM-BAPTA, and R2 contains EDTA. In the comparison table in the summary, the sample types are given as serum, lithium heparin plasma and urine, the calibrator as Calibrator f.a.s., and the calibration mode as two-point linear; the reagent is a ready-to-use liquid photometric reagent. The same summary states that calcium measurements are used in the diagnosis and treatment of parathyroid disease, various bone diseases, chronic kidney disease and tetany.
How the test is performed
For a calcium test, blood is drawn from a vein in the arm with a small needle, and the procedure usually takes less than five minutes. Mild pain or bruising may occur where the needle goes in; MedlinePlus states that these symptoms usually pass quickly. According to MedlinePlus, no special preparation is generally needed for a calcium test or for the basic and comprehensive metabolic panels.
A high or low result
According to MedlinePlus, a high total calcium result can point to overactive parathyroid glands, certain cancers including cancers that have spread to bone, bone diseases such as Paget’s disease, or excessive vitamin D intake over a long period. A low result can be due to low blood protein, underactive parathyroid glands, too little calcium in the diet, too little vitamin D or magnesium, pancreatitis and kidney disease. A value outside the normal range does not always mean a disease that requires treatment. A single calcium value does not establish a diagnosis; the physician interprets the result together with symptoms and, if necessary, additional tests.
Evaluation from the laboratory perspective
The performance studies in the FDA summary were carried out on the cobas c 501 analyzer. On which cobas c model the kit will be used should be confirmed from Roche’s current product information. The sample type (serum, plasma or urine) is also decisive for the consistency of the result. For usage details, the package insert of the kit should be consulted. The summary compares the test with Roche’s earlier calcium reagent (k921661) and states that the intended use is the same.
For product information, the Roche CA2 Gen.2 and CA2 test kit pages can be reviewed, and for other kits the test kits page. For price and supply information, the contact page can be used.
Frequently asked questions
According to Roche’s FDA 510(k) summary, it is defined for the quantitative determination of calcium in human serum, plasma and urine.
Total and ionized calcium are not the same measurement. Total calcium measures the sum of bound and free calcium, and ionized calcium measures only the free portion. According to MedlinePlus, these two forms are normally present in roughly equal amounts.
The FDA summary lists parathyroid disease, various bone diseases, chronic kidney disease and tetany. The result alone does not establish a diagnosis; the physician interprets it.