en

Total T4
system
7K66
49-1197/R3
B7K660
Read Highlighted Changes
Revised February, 2010

Total T4
Customer Service: Contact your local representative or find country specific contact information
on www.abbottdiagnostics.com
Package insert instructions must be carefully followed. Reliability of assay results cannot be guaranteed if there are any
deviations from the instructions in this package insert.

Key to symbols used

List Number Calibrator (1, 2)

Control Low, Medium,

In Vitro Diagnostic Medical High (L, M, H)
Device
Assay CD-ROM

Lot Number Reaction Vessels

Sample Cups
Expiration Date
Septum

Replacement Caps
Store at 2-8°C
Serial Number

Reagent Lot
Consult instructions for use
Warning: May cause an
allergic reaction
Contains sodium azide.
Manufacturer Contact with acids
liberates very toxic gas.

See REAGENTS section for a full explanation of symbols used in reagent

component naming.

1
NAME REAGENTS
ARCHITECT Total T4 Reagent Kit, 100 Tests / 500 Tests
INTENDED USE NOTE: Some kit sizes are not available in all countries or for use on all
ARCHITECT i Systems. Please contact your local distributor.
The ARCHITECT Total T4 (TT4) assay is a Chemiluminescent Microparticle
Immunoassay (CMIA) for the quantitative determination of thyroxine ARCHITECT Total T4 Reagent Kit (7K66)
(Total T4) in human serum and plasma. • 1 or 4 Bottle(s) (6.6 mL/27.0 mL) anti-T4 (sheep)
coated Microparticles in TRIS buffer with sheep IgG stabilizers.
SUMMARY AND EXPLANATION OF TEST Minimum concentration: 0.10% solids. Preservative: Sodium Azide.
Thyroxine (T4) is an iodine-containing hormone which has a molecular • 1 or 4 Bottle(s) (5.9 mL/26.3 mL) T3 acridinium-labeled
weight of approximately 777 daltons and is secreted by the thyroid gland. Conjugate in MES buffer with NaCl and Triton X-100 stabilizers.
T4 and its associate thyroid hormone T3 are responsible for regulating Minimum concentration: 0.2 ng/mL. Preservative: ProClin.
diverse biochemical processes throughout the body which are essential
for normal metabolic and neural activity.1 Other Reagents
Although T3 has greater biologic potency 2, T4 is normally present in ARCHITECT i Pre-Trigger Solution
human serum in approximately 50-fold excess of circulating T3 and • Pre-Trigger Solution containing 1.32% (w/v)
accounts for more than 90% of the circulating protein-bound iodine. T4 hydrogen peroxide.
is 99.9% bound to serum thyroxine binding proteins (TBP). The hormone ARCHITECT i Trigger Solution
is transported bound primarily to thyroxine binding globulin (TBG) and • Trigger Solution containing 0.35N sodium
secondarily by thyroxine binding prealbumin (TBPA) and albumin. 3 Less hydroxide.
than 0.05% of the total circulating T4 is unbound and therefore biologically
ARCHITECT i Wash Buffer
active.4,5 Clinically, T4 measurements have long been recognized as an
aid in the assessment and diagnosis of thyroid status. Elevated T4 values NOTE: Bottle and volume varies based on order.
are characteristically seen in patients with overt hyperthyroidism, while • Wash Buffer containing phosphate buffered saline
T4 levels are generally depressed in patients with overt hypothyroidism. solution. Preservatives: antimicrobial agents.
Normal T4 levels accompanied by high T3 values are seen in patients with WARNINGS AND PRECAUTIONS
T3-thyrotoxicosis.6 T4 levels are altered by physiological or pathological •
changes in TBP capacity.3,4 Thyroxine binding globulin (TBG) capacity
• For In Vitro Diagnostic Use
has a pronounced effect on the concentration of thyroid hormones.
Consequently, T4 levels may be elevated with increased concentrations • Package insert instructions must be carefully followed. Reliability of
of TBG, such as in pregnancy, administration of oral contraceptives assay results cannot be guaranteed if there are any deviations from
or estrogen, infectious and chronic active hepatitis, biliary cirrhosis the instructions in this package insert.
or congenital increase in TBG levels. 7-9 Conversely, when TBG levels Safety Precautions
are decreased, such as in nephrotic syndrome, androgen therapy, CAUTION: This product requires the handling of human specimens.
glucocorticoid therapy, major systemic illness or congenital decrease of It is recommended that all human sourced materials be considered
TBG, T4 may be reduced. potentially infectious and handled in accordance with the OSHA Standard
Drugs which compete for protein binding sites, such as phenylbutazone, on Bloodborne Pathogens 13. Biosafety Level 2 14 or other appropriate
diphenylhydantoin or salicylates, can result in a depressed biosafety practices 15,16 should be used for materials that contain or are
T4 measurement. 7-9 Serum T4 levels in neonates and infants are higher suspected of containing infectious agents.
than values in the normal adult, due to the increased concentration of • This product (the microparticles) contains sodium azide. Contact with
TBG in neonate serum.10 acids liberates very toxic gas. This material and its container must be
While in many cases T4 values give good indications of thyroid status, disposed of in a safe way.
T4 values should be normalized for individual variations in thyroxine binding The following warnings and precautions apply to this component:
protein (TBP) capacity. The Free Thyroxine Index (FTI) is conventionally • Conjugate
used to achieve this measurement.11,12
To ensure maximum diagnostic accuracy, the final definition of thyroid WARNING: Contains methylisothiazolones.
status should be determined in conjunction with other thyroid function H317 May cause an allergic skin reaction.
tests such as TSH, Free T4, Total T3, FTI and clinical evaluation by the Prevention
physician. P261 Avoid breathing mist / vapours / spray.
The ARCHITECT Total T4 assay is to be used as an aid in the assessment P272 Contaminated work clothing should not
of thyroid status. be allowed out of the workplace.
P280 Wear protective gloves / protective
BIOLOGICAL PRINCIPLES OF THE PROCEDURE clothing / eye protection.
The ARCHITECT Total T4 assay is a two-step immunoassay to determine
the presence of thyroxine (Total T4) in human serum and plasma using Response
Chemiluminescent Microparticle Immunoassay (CMIA) technology with P302+P352 IF ON SKIN: Wash with plenty of soap
flexible assay protocols, referred to as Chemiflex. and water.
In the first step, sample and anti-T4 coated paramagnetic microparticles P333+P313 If skin irritation or rash occurs: Get
are combined. Bound T4 is removed from the binding sites on thyroxine medical advice / attention.
binding globulin, prealbumin and albumin. T4 present in the sample binds P363 Wash contaminated clothing before use.
to the anti-T4 coated microparticles. After washing, T3 acridinium-labeled This material and its container must be disposed of in a safe way.
conjugate is added in the second step. Pre-Trigger and Trigger Solutions • For information on the safe disposal of sodium azide and a detailed
are then added to the reaction mixture; the resulting chemiluminescent discussion of safety precautions during system operation, refer to the
reaction is measured as relative light units (RLUs). An inverse relationship ARCHITECT System Operations Manual, Section 8.
exists between the amount of Total T4 in the sample and the RLUs
detected by the ARCHITECT i optical system.
For additional information on system and assay technology, refer to the
ARCHITECT System Operations Manual, Section 3.

2
Handling Precautions SPECIMEN COLLECTION AND PREPARATION FOR ANALYSIS
• Do not use reagent kits beyond the expiration date. • Human serum (including serum collected in serum separator tubes) or
• Do not mix reagents from different reagent kits. plasma collected in sodium heparin, lithium heparin (including plasma
• Prior to loading the ARCHITECT Total T4 Reagent Kit on the system separator tubes), or potassium EDTA anticoagulant tubes may be
for the first time, the microparticle bottle requires mixing to resuspend used in the ARCHITECT Total T4 assay. Other anticoagulants have not
microparticles that have settled during shipment. For microparticle been validated for use with the ARCHITECT Total T4 assay. Follow the
mixing instructions, refer to the PROCEDURE, Assay Procedure manufacturer’s processing instructions for serum or plasma collection
section of this package insert. tubes.
• Septums MUST be used to prevent reagent evaporation and • When serial specimens are being evaluated, the same type of
contamination and to ensure reagent integrity. Reliability of assay specimen should be used throughout the study.
results cannot be guaranteed if septums are not used according to • The ARCHITECT i System does not provide the capability to verify
the instructions in this package insert. specimen type. It is the responsibility of the operator to verify the
• To avoid contamination, wear clean gloves when placing a septum on correct specimen types are used in the ARCHITECT Total T4 assay.
an uncapped reagent bottle. • Use caution when handling patient specimens to prevent cross
• Once a septum has been placed on an open reagent bottle, do contamination. Use of disposable pipettes or pipette tips is
not invert the bottle as this will result in reagent leakage and may recommended.
compromise assay results. • Do not use heat-inactivated specimens.
• Over time, residual liquids may dry on the septum surface. These are • For optimal results, inspect all samples for bubbles. Remove bubbles
typically dried salts which have no effect on assay efficacy. with an applicator stick prior to analysis. Use a new applicator stick
• For a detailed discussion of handling precautions during system for each sample to prevent cross contamination.
operation, refer to the ARCHITECT System Operations Manual, • For optimal results, serum and plasma specimens should be free
Section 7. of fibrin, red blood cells or other particulate matter.
Storage Instructions • Ensure that complete clot formation in serum specimens has taken
place prior to centrifugation. Some specimens, especially those
from patients receiving anticoagulant or thrombolytic therapy may
• The ARCHITECT Total T4 Reagent Kit must be stored exhibit increased clotting time. If the specimen is centrifuged
at 2-8°C and may be used immediately after removal from 2-8°C before a complete clot forms, the presence of fibrin may cause
storage. erroneous results.
• When stored and handled as directed, reagents are stable until the • If testing will be delayed more than 24 hours, remove serum or plasma
expiration date. from the clot, serum separator or red blood cells. Specimens may be
• The ARCHITECT Total T4 Reagent Kit may be stored on-board the stored for up to 6 days at 2-8°C prior to being tested. If testing will be
ARCHITECT i System for a maximum of 30 days. After 30 days, the delayed more than 6 days, specimens should be frozen at -10°C or
reagent kit must be discarded. For information on tracking on-board colder. Specimens stored frozen at -10°C or colder for 6 days showed
time, refer to the ARCHITECT System Operations Manual, Section 5. no performance difference.
• Reagents may be stored on or off the ARCHITECT i System. If reagents • Multiple freeze-thaw cycles of specimens should be avoided.
are removed from the system, store them at 2-8°C (with septums and Specimens must be mixed THOROUGHLY after thawing, by LOW
replacement caps) in an upright position. For reagents stored off the speed vortexing or by gently inverting, and centrifuged prior to use
system, it is recommended that they be stored in their original trays and to remove red blood cells or particulate matter to ensure consistency
boxes to ensure they remain upright. If the microparticle bottle does in the results.
not remain upright (with a septum installed) while in refrigerated • When shipped, specimens must be packaged and labeled in compliance
storage off the system, the reagent kit must be discarded. After with applicable state, federal and international regulations covering
reagents are removed from the system, you must initiate a scan to the transport of clinical specimens and infectious substances. Prior
update the on-board stability timer. to shipment, it is recommended that specimens be removed from the
clot, serum separator or red blood cells.
Indications of reagent instability or deterioration
When a control value is out of the specified range, it may indicate PROCEDURE
deterioration of the reagents or errors in technique. Associated test Materials Provided
results may be invalid and may require retesting. Assay recalibration may • 7K66 ARCHITECT Total T4 Reagent Kit
be necessary. For troubleshooting information, refer to the ARCHITECT
Materials Required but not Provided
System Operations Manual, Section 10.
• ARCHITECT i System
INSTRUMENT PROCEDURE • ARCHITECT i
• The ARCHITECT Total T4 assay file must be installed on the • 7K66-01 ARCHITECT Total T4 Calibrators
ARCHITECT i System from the ARCHITECT i Assay CD-ROM prior to
• 7K66-10 ARCHITECT Total T4 Controls
performing the assay. For detailed instructions on assay file installation
and on viewing and editing assay parameters, refer to the ARCHITECT • ARCHITECT i
System Operations Manual, Section 2. • ARCHITECT i
• For information on printing assay parameters, refer to the ARCHITECT • ARCHITECT i
System Operations Manual, Section 5. • ARCHITECT i
• For a detailed description of system procedures, refer to the • ARCHITECT i
ARCHITECT System Operations Manual. • ARCHITECT i
• The default result unit for the ARCHITECT Total T4 assay is μg/dL. An • ARCHITECT i
alternate result unit, nmol/L, may be selected for reporting results by • For information on materials required for maintenance procedures,
editing assay parameter “Result concentration units”, to nmol/L. The refer to the ARCHITECT System Operations Manual, Section 9.
conversion factor used by the system is 12.87. • Pipettes or pipette tips (optional) to deliver the volumes specified on
the patient or control order screen.

3
Assay Procedure Specimen Dilution Procedures
Before loading the ARCHITECT Total T4 Reagent Kit on the system Specimens with a Total T4 value exceeding 24.00 μg/dL are flagged
for the first time, the microparticle bottle requires mixing to resuspend with the code “>24.00” and may be diluted with the Manual Dilution
microparticles that have settled during shipment: Procedure.
• Invert the microparticle bottle 30 times. • Manual Dilutions should be performed as follows:
• Visually inspect the bottle to ensure microparticles are • The suggested dilution for Total T4 is 1:2. It is recommended
resuspended. If microparticles are still adhered to the bottle, dilutions not exceed 1:2.
continue to invert the bottle until the microparticles have been • For a 1:2 dilution, add a minimum of 75 μL of the patient specimen
completely resuspended. to 75 μL of ARCHITECT Total T4 Calibrator 1.
• If the microparticles do not resuspend, DO NOT USE. Contact • To avoid contamination of Calibrator 1, dispense several drops of
your local Abbott representative. Calibrator 1 into a clean test tube prior to pipetting.
• Once the microparticles have been resuspended, remove and • The operator must enter the dilution factor (2) in the patient or control
discard the cap. Wearing clean gloves, remove a septum from the order screen. The system will use this dilution factor to automatically
bag. Carefully snap the septum onto the top of the bottle. calculate the concentration of the sample before dilution. This will
• Order tests. be the reported result. The dilution should be performed so that the
• Load the ARCHITECT Total T4 Reagent Kit on the ARCHITECT reported result reads greater than 6.0 μg/dL.
i System. Verify that all necessary assay reagents are present. Ensure • If the operator does not enter the dilution factor, the reported result
that septums are present on all reagent bottles. will be that of the diluted sample. This result (before dilution factor is
• The minimum sample cup volume is calculated by the system and applied) should be greater than 3.0 μg/dL.
is printed on the Orderlist report. No more than 10 replicates may • For detailed information on ordering dilutions, refer to the ARCHITECT
be sampled from the same sample cup. To minimize the effects of System Operations Manual, Section 5.
evaporation, verify adequate sample cup volume is present prior to
Calibration
running the test.
• To perform an ARCHITECT Total T4 calibration, test Calibrators 1 and
• Priority: 75 μL for the first Total T4 test plus 25 μL for each 2 in duplicate. A single sample of all levels of Total T4 controls must
additional Total T4 test from the same sample cup be tested to evaluate the assay calibration. Ensure that assay control
• ≤ 3 hours onboard: 150 μL for the first Total T4 test plus 25 μL for values are within the concentration ranges specified in the control
each additional Total T4 test from the same sample cup package insert. Calibrators should be priority loaded.
• > 3 hours onboard: additional sample volume is required. Refer • Calibrator Range: 0.0 - 24.0 μg/dL.
to the ARCHITECT System Operations Manual, Section 5 for • Once an ARCHITECT Total T4 calibration is accepted and stored,
information on sample evaporation and volumes. all subsequent samples may be tested without further calibration
• If using primary or aliquot tubes, use the sample gauge to ensure unless:
sufficient patient specimen is present. • A reagent kit with a new lot number is used.
• ARCHITECT Total T4 Calibrators and Controls should be mixed by • Controls are out of range.
gentle inversion prior to use.
• For detailed information on how to perform an assay calibration, refer
• To obtain the recommended 150 μL volume requirements for the to the ARCHITECT System Operations Manual, Section 6.
ARCHITECT Total T4 Calibrators and Controls, hold the bottles
vertically and dispense 4 drops of each calibrator or 4 drops of each QUALITY CONTROL PROCEDURES
control into each respective sample cup. The recommended control requirement for the ARCHITECT Total T4 assay
• Load samples. is a single sample of all control levels tested once every 24 hours each
• For information on loading samples, refer to the ARCHITECT System day of use. If the quality control procedures in your laboratory require more
Operations Manual, Section 5. frequent use of controls to verify test results, follow your laboratory-specific
procedures. Ensure that assay control values are within the concentration
• Press RUN. The ARCHITECT i System performs the following
ranges specified in the control package insert.
function:
• Moves the sample to the aspiration point Verification of Assay Claims
• Loads a reaction vessel (RV) into the process path For protocols to verify package insert claims, refer to the ARCHITECT
System Operations Manual, Appendix B. The ARCHITECT Total T4 assay
• Aspirates and transfers sample into the RV
belongs to method group 1.
• Advances the RV one position and transfers microparticles into
the RV RESULTS
• Mixes, incubates and washes the reaction mixture The ARCHITECT Total T4 assay utilizes a 4 Parameter Logistic Curve
• Adds conjugate to the RV Fit data reduction method (4PLC, X weighted) to generate a calibration
curve.
• Mixes, incubates and washes the reaction mixture
• Adds Pre-Trigger and Trigger Solutions Alternate Result Units
• Measures chemiluminescent emission to determine the quantity • The default result unit for the ARCHITECT Total T4 assay is μg/dL.
of Total T4 in the sample When the alternate result unit, nmol/L, is selected, the conversion
factor used by the system is 12.87.
• Aspirates contents of RV to liquid waste and unloads RV to solid
waste • Conversion Formula:
• Calculates the result (Concentration in μg/dL) x (12.87) = Concentration in nmol/L
• For information on ordering patient specimens, controls, and general Flags
operating procedures refer to the ARCHITECT System Operations • Some results may contain information in the Flags field. For a
Manual, Section 5. description of the flags that may appear in this field, refer to the
• For optimal performance, it is important to follow the routine maintenance ARCHITECT System Operations Manual, Section 5.
procedures defined in the ARCHITECT System Operations Manual,
Section 9. If your laboratory requires more frequent maintenance,
follow those procedures.

4
LIMITATIONS OF THE PROCEDURE Analytical Sensitivity
• For diagnostic purposes, results should be used in conjunction with The ARCHITECT Total T4 assay is designed to have an analytical sensitivity
other data; e.g., symptoms, results of other thyroid tests, clinical of ≤ 1.0 μg/dL.
impressions, etc. Analytical sensitivity is defined as the concentration calculated as the
• If the Total T4 results are inconsistent with clinical evidence, additional mean plus two standard deviations of replicates of the ARCHITECT Total T4
testing is suggested to confirm the result. MasterCheck Level 0 (0.0 μg/dL). The analytical sensitivity (low-linearity)
• Performance of this test has not been established with neonatal is defined in the ARCHITECT Total T4 assay parameters as 1.0 μg/dL.
specimens. Analytical Specificity
EXPECTED VALUES The ARCHITECT Total T4 assay is designed to have a mean analytical
A normal range of 4.87 μg/dL to 11.72 μg/dL (central 95% interval) was specificity of ≤ 3.2% cross reactivity with triiodothyronine (T3) at a
obtained by testing serum specimens from 437 individuals determined as concentration of 100 μg/dL in a sample containing approximately
normal by AxSYM Ultrasensitive hTSH II and AxSYM Free T4 assays. It is 3 μg/dL of Total T4 as confirmed by a study based on guidance from CLSI
recommended that each laboratory establish its own normal range, which document EP7-A.18
may be unique to the population it serves depending upon geographical, Interference
patient, dietary, or environmental factors. The ARCHITECT Total T4 assay is designed to have a mean potential
SPECIFIC PERFORMANCE CHARACTERISTICS interference from hemoglobin, bilirubin, triglycerides, and protein of < 10%
Precision at the levels indicated below as confirmed by a study based on guidance
The ARCHITECT Total T4 assay is designed to have a precision of ≤ 10% from CLSI document EP7-A.18
(total CV) for concentrations in the range of the low control (4.2 μg/dL), • Hemoglobin ≤ 500 mg/dL
medium control (7.4 μg/dL), and high control (14.6 μg/dL). • Bilirubin ≤ 20 mg/dL
A study based on guidance from Clinical and Laboratory Standards • Triglycerides ≤ 3000 mg/dL
Institute (CLSI, formerly NCCLS) document EP5-A 17 was performed for
• Protein ≥ 4.5 and ≤ 12 g/dL
the ARCHITECT Total T4 assay. A three member processed human serum
based panel was assayed, using two lots of reagents, in replicates of two Accuracy by Correlation
at two separate times per day for 20 testing days. Data from this study are The ARCHITECT Total T4 assay is designed to have a slope of 1.00 ± 0.20
shown in the following table.* and a correlation coefficient (r) of ≥ 0.90 when compared to the AxSYM
Mean Total T4 assay.
Conc. A study was performed where specimens were tested using ARCHITECT
Panel Reagent Instru- Value Within Run Total Total T4 assay and AxSYM Total T4 assay. Data from this study were
Member Lot ment n (μg/dL) SD %CV SD %CV analyzed using least squares and Passing Bablok 19 regression methods
1 1 1 80 4.20 0.155 3.7 0.188 4.5 and are summarized in the following table.*
1 2 1 80 4.32 0.176 4.1 0.196 4.5 Abbott ARCHITECT Total T4 vs. Abbott AxSYM Total T4
1 1 2 80 4.45 0.133 3.0 0.167 3.8 Number of Correlation
1 2 2 80 4.30 0.136 3.2 0.151 3.5 Method Specimens Intercept Slope Coefficient
2 1 1 80 7.46 0.251 3.4 0.300 4.0 Least Squares
2 2 1 80 7.35 0.222 3.0 0.268 3.6 Linear Regression 656 -0.26 0.96 0.97
2 1 2 80 7.90 0.234 3.0 0.301 3.8 Passing-Bablok
2 2 2 80 7.32 0.210 2.9 0.224 3.1 Linear Regression** 656 -0.20 0.94 0.97
3 1 1 80 14.87 0.896 6.0 1.084 7.3 In this evaluation, serum specimens tested ranged from 1.03 to
3 2 1 80 14.94 0.521 3.5 0.655 4.4 20.55 μg/dL with the ARCHITECT Total T4 assay and from 1.12 to
3 1 2 80 16.22 0.616 3.8 0.738 4.5 22.46 μg/dL with the AxSYM Total T4 assay.
3 2 2 80 15.13 0.595 3.9 0.703 4.6 * Representative data: variables such as differences in sampling size and
sample population may impact the correlation of the assay; therefore,
* Representative data; results in individual laboratories may vary from results in individual laboratories may vary from these data.
these data. ** A linear regression method with no special assumptions regarding the
Recovery distribution of the samples and the measurement errors.19
The ARCHITECT Total T4 assay is designed to have a mean recovery of BIBLIOGRAPHY
100 ± 10% when analyzing samples spiked with known amounts of T4. 1. Felig P, Baxter JD, Broadus AE, Frohman LA, editors. Endocrinology
T4 was added to five normal human serum samples. The concentration and Metabolism (2nd Ed.). New York: McGaw-Hill Book Co., 1987;
of Total T4 was determined using the ARCHITECT Total T4 assay and the 389-409.
resulting percent recovery was calculated.* 2. Lerman J. The Physiologic Activity of L-Triiodothyronine. J Clin
Observed Endocrinol Metab 1953;13:1341-1346.
Endogenous T4 Total T4 3. Oppenheimer JH. Role of Plasma Proteins in the Binding,
Concentration T4 Added Concentration % Distribution and Metabolism of the Thyroid Hormones. N Engl J Med
Sample (μg/dL) (μg/dL) (μg/dL) Recovery* 1968;278:1153-1162.
1 7.472 1.20 8.825 112.7 4. Robbins J, Rall JE. Thyroxine-Binding Proteins. In: Gray CH, Bacharach
2 7.301 1.20 8.487 98.9 AL, editors. Hormones in Blood (2nd Ed.). London: Academic Press,
3 7.574 1.20 8.631 88.2 1967;1:427-440.
5. Ekins RP, editor. Methods for the Measurement of Free Thyroid
4 6.760 1.20 7.911 95.9
Hormones. Amsterdam: Excerpta Medica Foundation. 1979;72-92.
5 8.547 1.20 10.015 122.3
6. Sterling K, Refetoff S, Selenkow HA. T3 Thyrotoxicosis: Thyrotoxicosis
Mean Recovery: 103.6% Due to Elevated Serum Triiodothyronine Levels. JAMA 1970;213:
571-575.
Observed Total T4 Conc. (μg/dL) -
7. Witherspoon LR, Shuler SE. Estimation of Free Thyroxine
Endogenous Total T4 Conc. (μg/dL)
* % Recovery = x 100 Concentration: Clinical Methods and Pitfalls. J Clin Immunoassay
T4 Added (μg/dL) 1984;7:192-205.
Representative data; results in individual laboratories may
vary from these data.

5
8. Bermudez F, Surks MI, Oppenheimer JH. High Incidence of Decreased
Serum Triiodothyronine Concentration in Patients with Nonthyroid
Disease. J Clin Endocrinol Metab 1975;41:27-40.
9. Larsen PR. Triiodothyronine: Review of Recent Studies of Its Physiology
and Pathophysiology in Man. Metabolism 1972;21:1073-1092.
10. Abuid J, Klein AH, Foley Jr TP, Larsen TP. Total and Free Triiodothyronine
and Thyroxine in Early Infancy. J Clin Endocrinol Metab 1974;39:
263-268.
11. Szpunar WE, Stoffer SS, Bednarz MN. Clinical Evaluation of a
Thyroxine-Binding Globulin Assay in Calculating a Free-Thyroxine
Index. J Nucl Med 1981;22:793-795.
12. Nusynowitz L. Free Thyroxine Index. JAMA 1975;232:1050.
13. US Department of Labor, Occupational Safety and Health
Administration, 29 CFR Part 1910.1030, Bloodborne pathogens.
14. US Department of Health and Human Services. Biosafety in
Microbiological and Biomedical Laboratories. 5th ed. Washington, DC:
US Government Printing Office; January 2007.
15. World Health Organization. Laboratory Biosafety Manual. 3rd ed.
Geneva: World Health Organization; 2004.
16. Clinical and Laboratory Standards Institute. Protection of Laboratory
Workers from Occupationally Acquired Infections: Approved Guideline
—Third Edition. CLSI Document M29-A3. Wayne, PA: Clinical and
Laboratory Standards Institute; 2005.
17. National Committee for Clinical Laboratory Standards, Evaluation
of Precision Performance of Clinical Chemistry Devices – Second
Edition; Approved Guideline. NCCLS Document EP5-A. Wayne, PA:
NCCLS; 1999.
18. National Committee for Clinical Laboratory Standards, Interference
Testing in Clinical Chemistry; Approved Guideline. NCCLS Document
EP7-A. Wayne, PA: NCCLS; 2002.
19. Passing H, Bablok W. A New Biometrical Procedure for Testing the
Equality of Measurements from Two Different Analytical Methods.
J Clin Chem. Clin Biochem. 1983;21:709-20.

AxSYM, ARCHITECT, Chemiflex and MasterCheck are trademarks of

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All trademarks are property of their respective owners.

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+353-43-3331000

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and
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February 2010
© 2006, 2010 Abbott Laboratories