Transferrin index: An alternative method for calculating the iron saturation of transferrin

J. Beilby, J. Olynyk, S. Ching, A. Prins, Nigel Swanson, William Reed, H. Harley, P. Garcia-Webb

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Abstract

We surveyed 140 clinical chemistry laboratories in Australia to establish which laboratory methods they used to determine serum iron status: 125 measured serum iron (Fe), 85 measured transferrin (TRF), 47 measured total iron-binding capacity (TIBC), and 14 measured both TRF and TIBC. Of the 55 laboratories routinely reporting TRF saturation (TS), 16 calculated TS directly as (Fe/TIBC) x 100, and 9 used [Fe/(TRF x 2)] x 100. Thirty laboratories measured TRF and converted it to an equivalent TIBC concentration; the derived TIBC was then used to calculate TS. We measured iron, TIBC, and TRF concentrations in 94 control subjects, 59 patients with alcoholic liver disease (ALD), and 20 with proven genetic hemochromatosis (GH). TS was compared with a transferrin index (TI = Fe/TRF) to determine whether both methods were sensitive for GH screening and which method gave the fewest false-positive results with discrimination limits of >55% and >1.0, respectively. All GH patients were detected by both TS and TI at these limits. One control subject had a TI>1.0, whereas three control subjects had a TS>55%. Nine patients with ALD had a TI>1.0 and 11 ALD patients had a TS>55%. Some iron-overload patients had lower than expected TS values compared with TI, possibly because of ferritin interference in the TIBC assay. Also, the precision of the TRF assay was better than that of the TIBC assay: CVs of 1.85-3.68% vs 6.17%. We therefore recommend that calculated TI replace TS in screening for iron overload.
Original languageEnglish
Pages (from-to)2078-2081
JournalClinical Chemistry
Volume38
Issue number10
Publication statusPublished - 1992

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Transferrin
Iron
Alcoholic Liver Diseases
Hemochromatosis
Liver
Iron Overload
Assays
Screening
Clinical Chemistry
Genetic Testing
Ferritins
Serum

Cite this

Beilby, J., Olynyk, J., Ching, S., Prins, A., Swanson, N., Reed, W., ... Garcia-Webb, P. (1992). Transferrin index: An alternative method for calculating the iron saturation of transferrin. Clinical Chemistry, 38(10), 2078-2081.
Beilby, J. ; Olynyk, J. ; Ching, S. ; Prins, A. ; Swanson, Nigel ; Reed, William ; Harley, H. ; Garcia-Webb, P. / Transferrin index: An alternative method for calculating the iron saturation of transferrin. In: Clinical Chemistry. 1992 ; Vol. 38, No. 10. pp. 2078-2081.
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abstract = "We surveyed 140 clinical chemistry laboratories in Australia to establish which laboratory methods they used to determine serum iron status: 125 measured serum iron (Fe), 85 measured transferrin (TRF), 47 measured total iron-binding capacity (TIBC), and 14 measured both TRF and TIBC. Of the 55 laboratories routinely reporting TRF saturation (TS), 16 calculated TS directly as (Fe/TIBC) x 100, and 9 used [Fe/(TRF x 2)] x 100. Thirty laboratories measured TRF and converted it to an equivalent TIBC concentration; the derived TIBC was then used to calculate TS. We measured iron, TIBC, and TRF concentrations in 94 control subjects, 59 patients with alcoholic liver disease (ALD), and 20 with proven genetic hemochromatosis (GH). TS was compared with a transferrin index (TI = Fe/TRF) to determine whether both methods were sensitive for GH screening and which method gave the fewest false-positive results with discrimination limits of >55{\%} and >1.0, respectively. All GH patients were detected by both TS and TI at these limits. One control subject had a TI>1.0, whereas three control subjects had a TS>55{\%}. Nine patients with ALD had a TI>1.0 and 11 ALD patients had a TS>55{\%}. Some iron-overload patients had lower than expected TS values compared with TI, possibly because of ferritin interference in the TIBC assay. Also, the precision of the TRF assay was better than that of the TIBC assay: CVs of 1.85-3.68{\%} vs 6.17{\%}. We therefore recommend that calculated TI replace TS in screening for iron overload.",
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Beilby, J, Olynyk, J, Ching, S, Prins, A, Swanson, N, Reed, W, Harley, H & Garcia-Webb, P 1992, 'Transferrin index: An alternative method for calculating the iron saturation of transferrin' Clinical Chemistry, vol. 38, no. 10, pp. 2078-2081.

Transferrin index: An alternative method for calculating the iron saturation of transferrin. / Beilby, J.; Olynyk, J.; Ching, S.; Prins, A.; Swanson, Nigel; Reed, William; Harley, H.; Garcia-Webb, P.

In: Clinical Chemistry, Vol. 38, No. 10, 1992, p. 2078-2081.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Transferrin index: An alternative method for calculating the iron saturation of transferrin

AU - Beilby, J.

AU - Olynyk, J.

AU - Ching, S.

AU - Prins, A.

AU - Swanson, Nigel

AU - Reed, William

AU - Harley, H.

AU - Garcia-Webb, P.

PY - 1992

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N2 - We surveyed 140 clinical chemistry laboratories in Australia to establish which laboratory methods they used to determine serum iron status: 125 measured serum iron (Fe), 85 measured transferrin (TRF), 47 measured total iron-binding capacity (TIBC), and 14 measured both TRF and TIBC. Of the 55 laboratories routinely reporting TRF saturation (TS), 16 calculated TS directly as (Fe/TIBC) x 100, and 9 used [Fe/(TRF x 2)] x 100. Thirty laboratories measured TRF and converted it to an equivalent TIBC concentration; the derived TIBC was then used to calculate TS. We measured iron, TIBC, and TRF concentrations in 94 control subjects, 59 patients with alcoholic liver disease (ALD), and 20 with proven genetic hemochromatosis (GH). TS was compared with a transferrin index (TI = Fe/TRF) to determine whether both methods were sensitive for GH screening and which method gave the fewest false-positive results with discrimination limits of >55% and >1.0, respectively. All GH patients were detected by both TS and TI at these limits. One control subject had a TI>1.0, whereas three control subjects had a TS>55%. Nine patients with ALD had a TI>1.0 and 11 ALD patients had a TS>55%. Some iron-overload patients had lower than expected TS values compared with TI, possibly because of ferritin interference in the TIBC assay. Also, the precision of the TRF assay was better than that of the TIBC assay: CVs of 1.85-3.68% vs 6.17%. We therefore recommend that calculated TI replace TS in screening for iron overload.

AB - We surveyed 140 clinical chemistry laboratories in Australia to establish which laboratory methods they used to determine serum iron status: 125 measured serum iron (Fe), 85 measured transferrin (TRF), 47 measured total iron-binding capacity (TIBC), and 14 measured both TRF and TIBC. Of the 55 laboratories routinely reporting TRF saturation (TS), 16 calculated TS directly as (Fe/TIBC) x 100, and 9 used [Fe/(TRF x 2)] x 100. Thirty laboratories measured TRF and converted it to an equivalent TIBC concentration; the derived TIBC was then used to calculate TS. We measured iron, TIBC, and TRF concentrations in 94 control subjects, 59 patients with alcoholic liver disease (ALD), and 20 with proven genetic hemochromatosis (GH). TS was compared with a transferrin index (TI = Fe/TRF) to determine whether both methods were sensitive for GH screening and which method gave the fewest false-positive results with discrimination limits of >55% and >1.0, respectively. All GH patients were detected by both TS and TI at these limits. One control subject had a TI>1.0, whereas three control subjects had a TS>55%. Nine patients with ALD had a TI>1.0 and 11 ALD patients had a TS>55%. Some iron-overload patients had lower than expected TS values compared with TI, possibly because of ferritin interference in the TIBC assay. Also, the precision of the TRF assay was better than that of the TIBC assay: CVs of 1.85-3.68% vs 6.17%. We therefore recommend that calculated TI replace TS in screening for iron overload.

M3 - Article

VL - 38

SP - 2078

EP - 2081

JO - Clinical Chemistry

JF - Clinical Chemistry

SN - 0009-9147

IS - 10

ER -

Beilby J, Olynyk J, Ching S, Prins A, Swanson N, Reed W et al. Transferrin index: An alternative method for calculating the iron saturation of transferrin. Clinical Chemistry. 1992;38(10):2078-2081.