IgG/Albumin Ratios, CSF/Blood (Sendout)

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General Information

Lab Name
IgG/Albumin Ratios, CSF/Blood (Sendout)
Lab Code
RCSRAT
Epic Name
IgG/Albumin Ratios, CSF/Blood
External Test Id
SFIG
Description

Useful for: Aiding in the diagnosis of multiple sclerosis and other central nervous system inflammatory conditions.

Ordering Requirements: This test requires both CSF and a blood sample collected within 7 days of each other or testing will be cancelled by Mayo Clinic Laboratories. See IgG/Albumin Ratios, Blood (Sendout) [XSFIGS] for accompanying blood collection test.

References
Synonyms
CSF Index, IgG (Immunoglobulin G) Synthesis Rate, IgG Index, SFIG
Components
Code Name
RCIGI Immunoglobulin G Index, CSF
RCIGG Immunoglobulin G, CSF
RCALB Albumin, CSF
RCIGAR IgG/Albumin, CSF
RCSYNR IgG Synthesis Rate, CSF
RSIGG Immunoglobulin G, Serum
RSIGAR IgG/Albumin, Serum
RCSALQ Albumin Quotient, CSF/Serum
RSALB Albumin, Serum

Interpretation

Method

IgG Index, CSF and IgG, Serum: Nephelometry

Albumin: Photometric

Reference Range
See individual components
Ref. Range Notes

Interpretation:

Cerebrospinal fluid (CSF) IgG synthesis rate indicates the rate of increase in the daily CSF production of IgG in milligrams per day. A result greater than 12 mg/24 h is elevated.

A CSF IgG index greater than 0.70 is elevated and indicative of increased synthesis of IgG.

Interferences and Limitations

Cautions: The cerebrospinal fluid index can be elevated in other inflammatory demyelinating diseases such as neurosyphilis, acute inflammatory polyradiculoneuropathy, and subacute sclerosing panencephalitis.

References

Ordering & Collection

Specimen Type
CSF
Collection

Collect 1 mL CSF in a sterile vial.

  • Preferred: Collection vial number 2.

Note: This test also requires serum collected within 7 days of CSF collection. See IgG/Albumin Ratios, Blood (Sendout) [XSFIGS].

Handling Instructions

Outside Laboratories:

  • This test requires both CSF and serum samples obtained within 7 days of each other.
  • CSF: Store and transport CSF sample refrigerated.
  • Blood: See IgG/Albumin Ratios, Blood (Sendout) [XSFIGS].
  • Indicate "CSF" or "serum" on the sample labels.
  • Send serum and CSF samples in the same package to avoid delays. Transport with a cold pack.

Stability (CSF): Refrigerated (Preferred): 28 days; Frozen: 28 days; Ambient: 14 days.

Quantity
Requested: 1 mL CSF
Minimum: 0.5 mL CSF

Processing

Receiving Instructions

Refrigerate CSF in a sterile vial.

This test must be ordered with IgG/Albumin Ratios, Blood (Sendout) [XSFIGS]. If serum and CSF samples arrive together at the lab, an HC1 task is not needed. Forward both samples to the Sendouts bench. If a CSF sample is received without blood:

  1. Review open HC1 Tasks and/or the patient's record in Sunquest Inquiry to determine if the XSFIGS sample was previously received in lab. If so, receive the RCSRAT order and deliver all samples to Sendouts.
  2. If CSF is received without an existing XSFIGS order, create a task in HC1 to hold the CSF sample (refrigerated) while waiting for the blood. Do not deliver to Sendouts until both samples are received.
  3. Contact the provider or client as needed if the other sample is not received in a timely manner.

Sendouts:

  • Order Mayo test: SFIG
  • Interfaced: Yes [Interface: 601; Workskeet: MARF]
  • Wait for both CSF (RCSRAT) and serum (XSFIGS) samples before batching the order across the interface.
  • Write the sample type ("CSF" or "serum") on the sample labels.
  • Rubberband the serum and CSF samples together.
  • Batch the RCSRAT order outbound over the interface. Track both CIDs to USENT.
    • The XSFIGS code is for serum collection only, and will not batch separately.

Stability (CSF): Refrigerated (Preferred): 28 days; Frozen: 28 days; Ambient: 14 days.

Misc Sendout

Performance

Lab Department
Sendouts Mayo Lab (RF)(MARF)
Frequency
Performed: Monday through Friday. Report Available: 2-5 days from sample receipt at Mayo Clinic Laboratories.
Available STAT?
No
Performing Location(s)
Sendout Mayo Clinic Laboratories
800-533-1710

200 First Street Southwest
Rochester, MN 55901

Billing & Coding

CPT Codes
82040, 82042, 82784x2
LOINC
14116-8
Interfaced Order Code
UOW3372