Streptococcal serology – Dnase, Blood

Diagnostic Use

Timing of streptoccal serology testing for evidence of preceding Group A streptoccal infection is important. Streptococcal antibodies rise during the first month after infection, plateau for 3-6 months before returning to normal levels at 6-12 months.

Department

Microbiology - Serology

Delphic Registration Code

STRP

Laboratory Handling

Phlebotomy

Serum only

Registration

Serum only

Laboratory

Serum only

Constituent Tests

• Streptococcal serology – ASO, Blood

Synonyms

ASO
Dnase

Turnaround Time

7 days

Test Code

2451

Specimen Type

• Serum

Specimen Requirements

Tube/Container Type:

Preferred

• Serum (Red Cap)

Acceptable

• Serum (Red Cap)
• SST II (Gold Cap)

Preferred Sample Volume (ml)

10.0

Minimum Sample Volume (ml)

5.0

No of Samples Required

1

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• Serum (Red Cap)

Acceptable

• Serum (Red Cap)

Preferred Sample Volume (ml)

5.0

Minimum Sample Volume (ml)

2.0

Additional Specimen Information

Serum only

Aliquot Instructions

Sample Type

• Serum

Minimum Volume (ml)

0.5

Transport to Lab

Chilled (2 - 8 degrees Celsius)
If overnight - Chilled (2 - 8 degrees Celsius)

Additional Referral/Aliquot Information

Preferred aliquot serum 2 mL

Interpretation

The cutoff values for serological evidence of Group A streptococcal disease vary dependent on the individual assay used by the laboratory. The reported values may deviate from those stated in the Ministry of Health Rheumatic Fever guideline.

Please Note: Method Change for Streptococcal DNAse B as from 12.06.2023. Fully quantitative results are now reported using Siemens N Latex assay by
nephelometry on Siemens BNII. Significant range >=200 U/ml across all age ranges.

Interpret in conjunction with Anti-Streptolysin O result.

Reference Intervals

Reported in international units per mL:

Normal Dnase B <200 for adults and <300 for school age children.

ASO                               DNASE B

<200 IU/ml                 <200 IU/ml                 ADULTS

<250 IU/ml                  <200 IU/ml                School Age children

<100 IU/ml                  <200 U/ml                  Pre-school children

 

Test Method

Semi-quantitative Colourimetric Assay

Non-Funded Test Cost

$43.28 (Exclusive of GST)

Billing Code

2451

Onset date of illness desirable.

Contact Information

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