bilirubin (total) in serum/plasma (TBIL)

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Reference interval

  • Male & Female: 0.2 - 1.3 mg/dL


The Kodak Ektachem Clinical Chemistry Slide (TBIL) is a dry, multilayered, analytical element coated on a clear polyester support. The analysis is based on a modification of the classical diazo reaction.

The reported concentration of total bilirubin is the sum of unconjugated bilirubin (Bu), mono & di-glucuronide conjugated bilirubin(Bc), & delta bilirubin (DELB), a bilirubin fraction covalently bound to albumin.

A 10 uL drop of patient sample is deposited on the slide & is evenly distributed by the spreading layer. This layer provides a reflective background for measuring the diazo products of bilirubin & contains all reagents necessary to determine total bilirubin.

The method uses dyphlline & surfactant to dissociate unconjugated bilirubin from albumin. Unconjugated bilirubin, conjugated bilirubin & albumin-linked bilirubin (delta) subsequently react with the diazonium salt 4-(N-carboxy- methylsufamyl) benzendiazonium hexafluorophosphate to produce azobilirubin chromophores that have similar molar absorptivities and absorbance maxima around 520 nm. The buffered control layer, which is below the spreading/reaction layer, contains a polymeric quaternary amine (a mordant) coated on a transparent support. The mordant is used to stabilize the azo dyes generated in the reaction layer & to increase the sensitivity of the assay.

The concentration of total bilirubin is determined by measuring the azobilirubin chromophores at two wavelengths through the transparent support. Reflectance measurements at 540 nm & 460 nm are taken after 5 minutes incubation at 37 C. The measurement at 460 nm is used to correct for spectral interferences.

The following reaction sequences are involved:

Total Bilirubin    --------------------->          Azobilirubin
                  [4-(N-carboxy-methylsulfamyl)-   Chromophores
                   benzenediazonium hexafluoro-

Clinical significance




No special patient preparation is necessary.

Sample Preparation: Collect the specimen by standard venipuncture technique. Remove serum promptly from clot & analyze as soon as possible.

Do not use this slide for samples from neonatal patients < 14 days old.

Special precautions: Protect specimens from light; direct exposure to sunlight is reported to cause as much as a 50% loss of serum bilirubin in one hour, especially when specimen is kept in capillary tubes. Exposure to normal laboratory light can result in significant loss of serum bilirubin after 2 to 3 hours. Refrigerate specimen if it cannot be analyzed immediately. Freeze specimen for long-term storage or shipment.

Minimum sample size of 0.5 milliliters with an optimum size of 1.0 mL or larger.

More general terms

Additional terms

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  1. Kodak Ektachem 700 Analyzer Operator's Manual, Kodak Clinical Products, Rochester, New York.
  2. Kodak Ektachem Slide Package Inserts, Kodak Clinical Products Rochester, New York.
  3. Kodak Ektachem Training Manual, Kodak Clinical Products, Rochester, New York.
  4. Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 10.
  5. Bilirubin, Total, Serum or Plasma Laboratory Test Directory ARUP:
  6. Panel of 15 tests Laboratory Test Directory ARUP:
  7. Panel of 7 tests Laboratory Test Directory ARUP:
  8. Mini Panel of 2 tests: Bilirubin, Total, Serum or Plasma . Bilirubin Direct Laboratory Test Directory ARUP:
  9. Serum Bilirubin Laboratory Test Directory ARUP:

Patient information

bilirubin in serum patient information