Ebola laboratory tests

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Michael Maddaleni, B.S.

Overview

Ebola would be categorized as a viral hemorrhagic fever. Antigen-capture enzyme-linked immunosorbent assay (ELISA) testing, IgM ELISA, polymerase chain reaction (PCR), and virus isolation can be used to diagnose a case of Ebola HF within a few days of the onset of symptoms. Persons tested later in the course of the disease or after recovery can be tested for IgM and IgG antibodies; the disease can also be diagnosed retrospectively in deceased patients by using immunohistochemistry testing, virus isolation, or PCR.[1]

Laboratory Findings

There are no specific laboratory findings of Ebola virus disease, the following table shows some nonspecific usually found:[2]

Laboratory findings
Test Findings
White blood cells count Leucopenia (1000 cells/μL)
Lymphopenia
Neutrophilia
Blood smear Left shift
Atypical lymphocytes
Liver function tests Raised aspartate aminotransferase
Raised alanine aminotransferase
Extended prothrombin time
Extended partial thromboplastin time
Proteins Hyperproteinemia
Urinalysis Proteinuria

Diagnostic tests

Diagnostic test Samples required Preparation & Storage Shipping Viruses to be confirmed
ELISA (serology) detects: Whole blood serum or plasma

Acute and convalescent††

Freeze or refrigerate

(as cold as possible)

Frozen on dry ice or ice packs or both†††† Ebola
Lassa
CCHF
Rift Valley
Marburg
Yellow fever
PCR detects:

DNA, RNA from the virus.

Whole blood or clot††

Tissues (fresh frozen) Serum/plasma

Refrigerate or freeze

Freeze

Frozen on dry ice or ice packs or both†††† Ebola
Lassa
CCHF
Rift Valley
Marburg
Yellow fever
Immunohisto-chemestry (liver) detects:

Viral antigen in cells

Liver biopsy from fatal cases Fix formalin (can be stored up to 6 weeks) Room temperature (do not freeze) Ebola
Lassa
CCHF
Rift Valley
Marburg
Yellow fever
Immunohisto-chemestry (skin) detects:

Viral antigen in cells

Skin biopsy from fatal cases (any site) Fix in formalin (can be stored up to 6 weeks) Room temperature (do not freeze) Ebola
Lassa
Immunohisto-chemestry (other tissues) detects:

Viral antigen in cells

Tissue biopsy from fatal cases

(other tissues, spleen, lung, heart, kidney)

Fix in formalin (can be stored up to 6 weeks) Room temperature (do not freeze) Ebola
Lassa
CCHF
Rift Valley
Marburg
Yellow fever

Whole blood can be used for enzyme-linked immunosorbent assay (ELISA) and may be frozen. Do not centrifuge suspected VHF specimens because this increases risk to the lab worker. If serum specimens have already been prepared these can be used. Place specimens in plastic tubes for shipping and storage and be sure that the tubes are sealed and properly labeled.
†† Collect acute-phase specimen when patient is admitted to hospital or diagnosed as suspected case and collect convalescent-phase specimen at death or when discharged from the hospital.
††† whole blood or tissue is preferred, although serum or plasma may provide results.
†††† Use both ice packs and dry ice to provide best results. If dry ice or ice packs are not available, sample may be shipped at room temperature and still provide valid results in most cases.

Ebola virus can be detected in fatal cases from a skin specimen using immunohistochemistry or RT-PCR tests developed by the Centers for Disease Control and Prevention (CDC). The skin specimen is fixed in formalin or chaotrope which kills the virus. The specimen is no longer infectious once it is placed in formalin or chaotrope and the outside of the vial has been decontaminated. This vial can be shipped by mail or hand carried to the lab without risk. Results are available within a week after the specimen arrives at the CDC.

References

  1. "Ebola Hemorrhagic Fever Information Packet" (PDF).
  2. Feldmann H, Geisbert TW (2011). "Ebola haemorrhagic fever". Lancet. 377 (9768): 849–62. doi:10.1016/S0140-6736(10)60667-8. PMC 3406178. PMID 21084112.

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