Applicable To Employees of the Gundersen Boscobel Area Hospital Laboratory and Gundersen Palmer Lutheran Hospital and Clinics laboratories.

Transcription

1 Subject Calcium C311 Index Number Lab-8810 Section Laboratory Subsection Regional/Affiliates Category Departmental Contact Judy Dayton Last Revised 4/11/2017 References Required document for Laboratory Accreditation by the College of American Pathologists (CAP), Centers for Medicare and Medicaid Services (CMS) and/or COLA. Applicable To Employees of the Gundersen Boscobel Area Hospital Laboratory and Gundersen Palmer Lutheran Hospital and Clinics laboratories. Detail PRINCIPLE: This is an In vitro test for the quantitative determination of calcium in human serum, plasma and urine on Roche/Hitachi COBAS C311 systems. Calcium ions react with 5-nitro-5 -methyl-bapta (NM-BAPTA) under alkaline conditions to form a complex. This complex reacts in the second step with EDTA. The change in absorbance is directly proportional to the calcium concentration and is measured photometrically. CLINICAL SIGNIFICANCE: Calcium is the most abundant mineral element in the body with about 99 percent in the bones primarily as hydroxyapatite. The remaining calcium is distributed between the various tissues and the extracellular fluids where it performs a vital role for many life sustaining processes. Among the extra skeletal functions of calcium are involvement in blood coagulation, neuromuscular conduction, excitability of skeletal and cardiac muscle, enzyme activation, and the preservation of cell membrane integrity and permeability. Serum calcium levels and hence the body content are controlled by parathyroid hormone (PTH), calcitonin, and vitamin D. An imbalance in any of these modulators leads to alterations of the body and serum calcium levels. Increases in serum PTH or vitamin D are usually associated with hypercalcemia. Increased serum calcium levels may also be observed in multiple myeloma and other neoplastic diseases. Hypocalcemia may be observed in hypoparathyroidism, nephrosis, and pancreatitis. SPECIMENS: Universal Precautions apply. Serum, Li-heparin and Urine are acceptable. Lab-8810 Calcium C311 Page 1 of 5

2 Serum or plasma should be separated from blood cells as soon as possible, because prolonged contact with the clot may cause lower calcium values. Sera from patients receiving EDTA (treatment of hypercalcemia) are unsuitable for analysis, since EDTA will chelate the calcium and render it unavailable for reaction with NM-BAPTA. Co-precipitation of calcium with fibrin (i.e. heparin plasma), lipids, or denatured protein has been reported with storage or freezing. Specimen Stability: Serum/plasma 24 hours in primary gel tube at 2-8 o C 3 days at 2-8 o C if specimen poured off gel. Urine 2 days at o C 4 days at 2-8 o C 3 weeks at -20 o C REAGENTS/MATERIALS: R1 CAPSO: 557 mmol/l; NM-BAPTA: 2 mmol/l; ph 10.0; non-reactive surfactant and stabilizer R2 EDTA: 7.5 mmol/l; ph 7.3; non-reactive surfactant, preservative a) 3-[cyclohexylamino]-2-hydroxy-1-propanesulfonic acid R1 is in position B and R2 is in position C. Reagent Precautions: Exercise the normal precautions required for handling all laboratory reagents. Disposal of all waste material should be in accordance with local guidelines. Reagent Storage and Stability: CA2 Shelf life at 2-8 C: On-board in use and refrigerated on the analyzer: Diluent NaCl 9 % Shelf life at 2-8 C: On-board in use and refrigerated on the analyzer: See expiration date on cobas c pack label. 6 weeks See expiration date on cobas c pack label. 12 weeks EQUIPMENT/INSTRUMENTATION: COBAS C311 Calibration: Calibrator: Calibrator f.a.s. Use deionized water as zero calibrator. Calibrator Mode: Linear Calibration Frequency: The instrument should be calibrated: 1. at initial installation Lab-8810 Calcium C311 Page 2 of 5

3 2. if necessary after instrument service or repair 3. if dictated by quality control results 4. if instructed to do so by Roche support personnel 5. After reagent lot change QUALITY CONTROL: Quality Control Frequency Two levels of Quality Control should be performed at a minimum: 1. once every twenty-four hours 2. if a new cassette of reagent is put in use 3. if a calibration is performed Implementation Refer to the C311 User s Manual located in the laboratory. PROCEDURE NOTES: AMR (Analytic Measurement Range): Serum: mg/dl. Report values greater than 20 as > 20 mg/dl. Urine: mg/dl. If the concentration of a urine specimen is greater than 30 mg/dl, retest the specimen in Decrease mode. The extended range for urine specimens is mg/dl. For urine specimens: Measure and record volume of entire 24 hour collection. Pour off an aliquot to hold do not adjust PH. Add 6N HCI to remaining 24 hour collection until ph is 3-4. (Perform under hood wearing safety glasses.) Mix well. Let sit for 30 minutes to dissolve calcium salts. Mix well and obtain aliquot for assay. CALCULATIONS: Random urines are reported in mg/dl. Timed urines are reported in mg/24 hrs. Urine Calcium (mg/dl) X TV (ml/24hrs) 100 = Calcium mg/24 hrs. INTERPRETATION: Interpretation and Expected Ranges: Serum/plasma: mg/dl Urine: mg/24 hrs. LIMITATIONS: Criterion: Recovery within ± 0.22 mmol/l (0.9 mg/dl) of initial value of samples < 2.2 mmol/l (8.8 mg/dl) and within ± 10 % for samples > 2.2 mmol/l. Lab-8810 Calcium C311 Page 3 of 5

4 Serum/plasma Icterus: No significant interference up to an I index of 60 for conjugated and unconjugated bilirubin (approximate conjugated and unconjugated bilirubin concentration: 1026 µmol/l or 60 mg/dl). Hemolysis: No significant interference up to an H index of 1000 (approximate hemoglobin concentration: 621 µmol/l or 1000 mg/dl). Lipemia (Intralipid): No significant interference up to an L index of There is a poor correlation between the L index (corresponds to turbidity) and triglycerides concentration. Magnesium: No significant interference up to a concentration of 15 mmol/l. Drugs: No interference was found at therapeutic concentrations using common drug panels. The interference of intravenously administered gadolinium containing MRI (magnetic resonance imaging) contrast media was tested (Omniscan, Optimark ) but no interference was found at the therapeutic concentration. Interferences at higher concentrations were observed. In very rare cases, gammopathy, in particular type IgM (Waldenström's macroglobulinemia), may cause unreliable results. Urine Icterus: No significant interference up to a conjugated bilirubin concentration of 1026 µmol/l or 60 mg/dl. Hemolysis: No significant interference up to a hemoglobin concentration of 621 µmol/l or 1000 mg/dl. Magnesium: No significant interference up to a concentration of 60 mmol/l. Drugs: No interference was found at therapeutic concentrations using common drug panels. The interference of intravenously administered gadolinium containing MRI (magnetic resonance imaging) contrast media was tested (Omniscan, Optimark ). For Omniscan no interference was observed at the therapeutic concentration, but there was interference at higher concentrations. For Optimark interference was observed at therapeutic and higher concentrations. For diagnostic purposes, the results should always be assessed in conjunction with the patient's medical history, clinical examination and other findings. Special Wash Programming: The use of special wash steps is mandatory when certain test combinations are run together on Roche/Hitachi cobas c systems. The latest version of the carry-over evasion list can be found with the NaOHD/SMS/Multiclean/SCCS or the NaOHD/SMS/SmpCln1+2/SCCS Method Sheets. For further instructions refer to the operator's manual. Where required, special wash/carry-over evasion programming must be implemented prior to reporting results with this test. Lab-8810 Calcium C311 Page 4 of 5

5 REVIEW AND CHANGES: This document and all attached forms should be reviewed optimally on an annual basis, with two years as the maximum review date. Review will be done by the Technical Leader, Supervisor, Manager, Medical Director or other designated person. Changes require retyping the document, and review by the Medical Director. REFERENCES: 1. COBAS C311 User s Manual 2. COBAS C311 Calcium Method Sheet 3. COBAS C311 Method Manual Lab-8810 Calcium C311 Page 5 of 5