Test Catalog

Test Id : SDEX

Sickle Solubility, Blood

Useful For
Suggests clinical disorders or settings where the test may be helpful

Screening for presence or absence of hemoglobin (Hb) S (sickle cell disease)

Method Name
A short description of the method used to perform the test

Hemoglobin S Solubility

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Sickle Solubility, B

Lists additional common names for a test, as an aid in searching

Sickle Cell Screen


Sickling Test

Hemoglobin,Solubility Test for HbS

Specimen Type
Describes the specimen type validated for testing

Whole Blood EDTA

Ordering Guidance

This is a screening test only. For quantification of hemoglobin S, order HBEL1 / Hemoglobin Electrophoresis Evaluation, Blood.

Necessary Information

1. Patient's age is required.

2. Include recent transfusion information.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing


Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD solution B), green top (heparin)

Specimen Volume: 1 mL


If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.5 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Whole Blood EDTA Refrigerated 14 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Screening for presence or absence of hemoglobin (Hb) S (sickle cell disease)

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Homozygous hemoglobin (Hb) S (sickle cell disease) is a serious chronic hemolytic anemia most commonly found in those of African or Middle Eastern descent.


Hb S is freely soluble when fully oxygenated; when oxygen is removed, polymerization of the abnormal hemoglobin occurs, forming tactoids that are rigid and deformed cells. This leads to sickling of the cells, hemolysis, and many other complications.


Heterozygous Hb S (sickle cell trait) is the most common hemoglobinopathy in the United States. This condition is present in about 8% of African Americans. Usually, Hb S trait exhibits no clinical or hematological effects. A small fraction of people with sickle cell trait have recurrent hematuria.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.


Provides information to assist in interpretation of the test results

A positive result should be followed by a complete hemoglobin (Hb) evaluation (HBEL1 / Hemoglobin Electrophoresis Evaluation, Blood) to confirm the presence and concentration of Hb S.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

A positive test is presumptive evidence for hemoglobin (Hb) S (sickle cell disease). However, rare sickling Hbs such as Hb C-Harlem (C-Georgetown) and Hb I will also produce a positive result.


This test only detects the presence of Hb S. It cannot differentiate sickle cell trait (heterozygous Hb S) from sickle cell disease (homozygous Hb S), or Hb S in combination with other abnormalities (eg, S/C, S/D, S/G, S/E, S/beta-thalassemia, S/O-Arab, S/New York, and C-Georgetown trait).


The use of packed red blood cells (RBC) instead of whole blood significantly reduces false negatives due to anemia and false positives due to hypergammaglobulinemia (eg, multiple myeloma).


False positives can occur due to large numbers of nucleated RBC.


False negatives can occur due to an insufficient quantity of Hb S due to age (neonates) or transfusion. Hb S concentrations 15% to 20% or less may give a negative result.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Fairbanks VF: Laboratory methods and case studies. In: Decker BC, ed. Hemoglobinopathies and Thalassemias. Thieme-Stratton Inc; 1980: 105-107

2. Sauntharajah Y, Vichinsky EP: Sickle cell disease: Clinical features and management. In Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Elsevier; 2018:584-607

Method Description
Describes how the test is performed and provides a method-specific reference

Hemoglobin S reduced by dithionite is insoluble in concentrated inorganic buffers, and thus, the solution is so turbid that newsprint cannot be read through a tube containing the hemolysate and reagents.(Fairbanks VF, Klee GG: Biochemical aspects of hematology. In: Burtis CA, Ashwood ER, eds. Tietz Textbook of Clinical Chemistry. 3rd ed. WB Saunders Company; 1999: 1678-1679; Greene DN, Vaughn CP, Crews BO, Agarwal AM: Advances in the detection of hemoglobinopathies. Clinica Chimica Acta. 2015; 439:50-57)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

1 to 4 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
SDEX Sickle Solubility, B 6864-3
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
9180 Sickle Solubility, B 6864-3

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports

Test Update Resources

Change Type Effective Date
File Definition - Result ID 2021-03-22