This procedure is valid for the following chemistry analyzers:
Supersedes Procedure #
Serum albumin measurements are used in the diagnosis of numerous diseases. Elevated serum albumin levels are usually the result of dehydration. Decreased serum albumin levels are found in a number of conditions including kidney disease, liver disease, infections, severe burns and cancer.1
System reagent for the quantitative determination of Albumin in human serum or plasma on Beckman Coulter AU Clinical Chemistry analyzers.
Albumin reagent OSR6602 is for use on the AU2700and AU5400 analyzers only.
In 1965, Rodkey2 introduced a convenient, direct method for determining albumin concentrations in serum utilizing a neutral buffered solution of bromocresol green (BCG) as the dye binding indicator. In 1971, Doumas et al.3 increased the sensitivity of the reaction by adding a nonionic surfactant to the reagent to prevent turbidity and improve linearity. The Beckman Coulter AU System Albumin method is a modification of the Doumas and Rodkey procedures utilizing a different buffering system.
At pH 4.2, bromocresol green reacts with albumin to form an intense green complex. The absorbance of the albumin-BCG complex is measured bichromatically (600/800nm) and is proportional to the albumin concentration in the sample.
pH 4.2 Albumin + Bromocresol Green Complex
Additional instructions for patient preparation as designated by this laboratory:
Serum, heparinized or EDTA plasma samples, free from hemolysis, are the recommended specimens. Separate from blood cells as soon as possible.
Additional type conditions as designated by this laboratory:
Albumin is stable in serum for one week at room temperature (15 - 25°C) and for one month refrigerated (2 - 8°C).4
Additional handling conditions as designated by this laboratory:
Storage location of the calibrator in this laboratory:
For in vitro diagnostic use.
WARNING! IRRITANT! May cause sensitization by skin contact. Avoid contact with skin. In case of external contact, rinse affected areas with plenty of water.
WARNING: POTENTIAL BIOHAZARDOUS MATERIAL. The calibrator is manufactured from human serum. No test method can offer complete assurance that HIV- 1/2, HCV, Hepatitis B, or other infectious agents are absent from biological materials, all calibrator material should be handled at the Biosafety Level 2 as recommended for any infectious human serum or blood specimen in the CDC/National Institutes of Health manual, Biosafety in Microbiological and Biomedical Laboratories, 1993.
The Beckman Coulter AU System Albumin Reagent is liquid, ready for use. No preparation is needed.
For OSR6602, insert the pipe supplied into the 180mL AU reagent vials before use on the analyzer. Care must be taken when handling the pipe to avoid contamination. The pipe is for single use only. Do not remove the large cap on the 180mL bottles.
The Beckman Coulter Chemistry Calibrator reconstitution:
Remove the vials of calibrator and diluent from storage and let stand at room temperature (15-25C) for 5 minutes.
Remove the cap and stopper from the vials of the lyophilized serum and reconstituting diluent.
Using a volumetric pipette or a calibrated air-displacement pipettor, add exactly 5.0 mL of reconstituting diluent to DR0070 lyophilized serum vial. DO NOT pour directly from the reconstituting diluent vial.
Replace the cap and stopper to the vial of lyophilized serum immediately after adding the diluent
Allow the calibrator to stand for 5-10 minutes. Gently swirl the contents until completely dissolved.
1. The unopened reagents are stable until the expiration date printed on the label when stored at 2 - 25°C.
2. Opened reagents are stable for 90 days when stored in the refrigerated compartment of the analyzer.
Contamination after opening must be avoided.
Un-reconstituted calibrator and diluent are stable until the expiration date stated on the label when stored at 2 - 8°C.
For Albumin, reconstituted calibrator materials are stable for 7 days from the date of reconstitution when stored at 2 - 8°C. The materials should be capped and stored upright 2 - 8°C when not in use
Additional storage requirements as designated by this laboratory:
Indications of Deterioration:
Discoloration of the reagent, visible signs of microbial growth, turbidity or precipitation in reagent may indicate degradation and warrant discontinuance of use.
The following data was obtained using this Albumin Reagent on Beckman Coulter AU analyzers according to established procedures. Results obtained at individual facilities may differ.
Estimates of precision, based on CLSI recommendations8, are consistent with typical performance. The within run precision is less than 3%CV and total precision is less than 3%CV. Assays of control sera were carried out and data reduced following CLSI guidelines.
Patient samples were used to compare this Albumin Reagent. Representative performance data on AU analyzers is shown in the next table.
Correlation Coeff. (r)
No. of Samples (n)
Typical change in absorbance for 1 g/dL of Albumin is 138 Absorbance.
The frequency of calibration is every 30 days. Calibration of this albumin procedure is accomplished by use of the Beckman Chemistry Calibrator (Cat No DR0070), which is traceable to the College of American Pathology (CAP) Reference Preparation for Serum Protein # 4.
Recalibration of this test is required when any of these conditions exist:
A reagent lot number has changed or there is an observed shift in control values.
Major preventative maintenance was performed on the analyzer.
3. A critical part was replaced.
During operation of the Beckman Coulter AU analyzer at least two levels of an appropriate quality control material should be tested a minimum of once a day. In addition, controls should be performed after calibration, with each new lot of reagents, and after specific maintenance or troubleshooting steps described in the appropriate AU User’s Guide. Quality control testing should be performed in accordance with regulatory requirements and each laboratory’s standard procedure.
Location of controls used at this laboratory.
A complete list of test parameters and operating procedures can be found in the appropriate User’s Guide and at www.beckmancoulter.com.
For SI units (g/L), multiply the results by 10.
New Born4: 2.8 - 4.2 g/dL
Recumbent Adult4: 3.5 - 5.0 g/dL
Ambulatory Female4: 3.7 - 5.3 g/dL
Ambulatory Male4: 4.2 - 5.5 g/dL
Beckman Determined Range7: 3.5 - 5.7 g/dL
Expected values may vary with age, sex, diet and geographical location. Each laboratory should determine its own expected values as dictated by good laboratory practice.
Expected reference ranges in this laboratory:
Procedures for Abnormal Results:
Abnormal results are flagged by the listed analyzers according to the normal values entered by the user into the instrument parameters.
Results are automatically printed for each sample in g/dL at 37°C.
Additional reporting information as designated by this laboratory:
The Beckman Coulter AU System Albumin procedure is linear from 1.5 to 6.0 g/dL. Samples exceeding the upper limit of linearity should be diluted and repeated. The sample may be diluted, repeated and multiplied by the dilution factor automatically utilizing the AUTO REPEAT RUN.
Results of studies5 show that the following substances interfere with this albumin procedure.
The criteria for no significant interference is recovery within 10% of the initial value.
No significant interference up to 40 mg/dL Bilirubin
No significant interference up to 450 mg/dL Hemolysate
No significant interference up to 800 mg/dL Intralipid*
* Intralipid, manufactured by KabiVitrium Inc., is a 20% IV fat emulsion used to emulate extremely turbid samples.
The information presented is based on results from Beckman Coulter studies and is current at the date of publication. Beckman Coulter Inc., makes no representation about the completeness or accuracy of results generated by future studies. For further information on interfering substances, refer to Young6 for a compilation of reported interferences with this test.