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Trial registered on ANZCTR

Registration number
Ethics application status
Not yet submitted
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Laser doppler flowmetry in anaesthetic allergy skin testing
Scientific title
Laser doppler flowmetry versus conventional skin prick testing in anaesthetic allergy skin testing in patients over the age of 18 referred to allergy clinic with suspected anaphylaxis.
Secondary ID [1] 282561 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Anaphylaxis (antibody mediated allergic reaction) 289228 0
Anaphylactoid (non antibody mediated) allergic reaction 289229 0
Condition category
Condition code
Anaesthesiology 289562 289562 0 0
Other anaesthesiology
Inflammatory and Immune System 289563 289563 0 0

Study type
Description of intervention(s) / exposure
Laser Doppler flowmetry (LDF) is an inexpensive, non-invasive method of measuring the blood flow in the small vessels of the skin. In allergic patients, following skin testing the small blood vessels in the skin open and blood flow increases. This can be detected by LDF in a manner that is more objective.

The laser used in LDF is a Moor FLPI-2. It is classified as a “class 1” laser. The product information states it is “safe to use without eye protection”. The Monash University OHS website states that class 1 lasers “…are safe under most circumstances and are incapable of damaging the eyes or skin because of either engineered design or inherently low power output”.

The study will involve testing concurrently, at the same site, conventional skin testing and LDF testing.

Conventional skin testing will be undertaken to the drugs that the patient was exposed to perioperatively that could have been potential causal agents for allergy. Therefore the drugs tested will be specific to each individual case and we cannot predict what drugs will be skin tested as that depends on what drugs were administered during the anaesthetic.

Our testing involves intradermal administration of all the drugs that were given. Intradermal testing involves giving 0.02ml of dilute drug into the dermis of the skin. The dilutions vary depending on the drug from 1:100 to 1:100 000. That equates to about one millionth of the dose of the drug that was administered in the anaesthetic. We also do a positive control - that is a skin prick test (much <0.02mL) of 8mg/ml histamine.

Here is a list of drugs that may be required to be tested:

Drug Dilution Original concentration
Alfentanil 100 0.5 mg/mL
Amoxicillin 100 100 mg/mL
Atracurium 10,000 10 mg/mL
Atropine 1,000 600 mcg/mL
Bupivacaine 100 2.5 mg/mL (0.25%)
Cephazolin 100 100 mg/mL
Chlorhexidine 1,000 0.20%
Cisatracurium 1,000 2 mg/mL
Clindamycin 100 150mg/mL
Codeine 1,000 50 mg/mL
Dexamethasone 100 4mg/mL
Diazepam 100 5 mg/mL
Diclofenac 1,000 75 mg/mL
Droperidol 1,000 5 mg/mL
Erythromycin 1,000 50mg/mL
Fentanyl 100 50 mcg/mL
Gelofusine 100
Gentamicin 100 40 mg/mL
Glycopyrolate 100 200 mcg/mL
Granisetron 1000 1 mg/mL
Iodine 100 5% (Half)
Ketamine 100 20 mg/mL
Lignocaine 100 10 mg/mL (1%)
Metoclopromide 1,000 5 mg/mL
Midazolam 20 1 mg/mL
Mivacurium 1,000 2 mg/mL
Morphine 100,000 10 mg/mL
Neostigmine 1,000 2.5 mg/mL
Ondansetron 1000 2 mg/mL
Pancuronium 1,000 2 mg/mL
Paracetamol 100 10 mg/mL
Parecoxib 1,000 10 mg/mL
Patent blue 100 Half strength
Pethidine 100,000 50 mg/mL
Prilocaine 100 10 mg/mL (1%)
Propofol 100 10 mg/mL
Protamine 1,000 50 mg/mL
Remifentanil 1,000 0.5 mg/mL
Rocuronium 1,000 10 mg/mL
Ropivacaine 100 2 mg/mL (0.2%)
Suxamethonium1,000 50 mg/mL
Thiopentone 100 25 mg/mL
Tropisetron 100 1 mg/mL
Vancomycin 10,000 50 mg/mL
Vecuronium 1,000 4 mg/mL

One clinician will inject all the drugs to be tested into the skin at the same time as per conventional skin testing protocols. At 20 minutes after skin injection, a second clinician will assess the patient’s test site, again, using conventional skin testing protocols. The LDF testing will be recorded by the first clinician and stored on a password protected, specifically assigned computer.

At another time (to allow blinding) the second clinician will assess the LDF results.

The conclusions made using both assessment methods will be compared.
Intervention code [1] 287225 0
Diagnosis / Prognosis
Comparator / control treatment
LDF is compared to conventional skin prick testing which is the gold standard test for identification of anaesthetic agents that a patient is allergic to. This currently involves injecting diluted drug into the skin and measuring the swelling (wheal) and redness (flare) that has developed after 20 minutes. The clinician makes these measurements with a device such as a ruler or callipers
Control group

Primary outcome [1] 289657 0
Comparable positive or negative test result by LDF to the conventional skin testing method.
Timepoint [1] 289657 0
At 20minutes following injection of diluted drug, measured concurrently (by LDF device) with conventional skin testing (by clinician).
Secondary outcome [1] 302963 0
Timepoint [1] 302963 0

Key inclusion criteria
All patients scheduled for anaesthetic allergy testing at Sir Charles Gairdner Hospital.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Unable to give informed consent
Aged less than 18 years
Pregnant women
Patient refusal

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
All patients referred to allergy clinic at Sir Charles Gairdner Hospital that have consented and do not satisfy any of the exclusion criteria will have the intervention (LDF).
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 1053 0
Sir Charles Gairdner Hospital - Nedlands
Recruitment postcode(s) [1] 6913 0
6009 - Nedlands

Funding & Sponsors
Funding source category [1] 287343 0
Self funded/Unfunded
Name [1] 287343 0
Nil funding required.
Address [1] 287343 0
Country [1] 287343 0
Primary sponsor type
Dr Russell Clarke
Anaesthesia Department, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, Western Australia 6009
Secondary sponsor category [1] 286114 0
Name [1] 286114 0
Address [1] 286114 0
Country [1] 286114 0

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 289331 0
Sir Charles Gairdner Hospital Group Human Research Ethics Committee
Ethics committee address [1] 289331 0
Human Research Ethics Committee Office
2nd Floor, A Block
Sir Charles Gairdner Hospital,
Hospital Avenue NEDLANDS WA 6009
Ethics committee country [1] 289331 0
Date submitted for ethics approval [1] 289331 0
Approval date [1] 289331 0
Ethics approval number [1] 289331 0

Brief summary
Aims / Objectives
To compare the results from a Laser Doppler Flowmetry -based test against the current gold standard protocols for skin testing in patients suspected of severe allergic reaction.

LDF-based testing is as accurate as conventional skin testing protocols in assessing anaesthetic allergy.

Significance of project
LDF-based testing is objective, inexpensive and non-invasive. This may prove to be a valid alternative to conventional skin testing and may facilitate the identification of an allergic agent in patient’s that have proven to be difficult using previous testing protocols. It may present a faster, more efficient and reliable method of undertaking skin testing with the potential to discriminate between two main causes of serious allergic reaction (currently indistinguishable); Anaphylactic (IgE mediated allergy) versus anaphylactoid (direct histamine amplification).
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 40286 0
Dr Russell Clarke
Address 40286 0
Anaesthetic department, Sir Charles Gairdner Hospital, Hospital Avenue Nedlands, Western Australia 6009
Country 40286 0
Phone 40286 0
+61412 288 818
Fax 40286 0
+61 8 9346 4375
Email 40286 0
Contact person for public queries
Name 40287 0
Dr Russell Clarke
Address 40287 0
Anaesthetic department, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, Western Australia 6009
Country 40287 0
Phone 40287 0
+61412 288 818
Fax 40287 0
+61 8 9346 4375
Email 40287 0
Contact person for scientific queries
Name 40288 0
Dr Russell Clarke
Address 40288 0
Anaesthetic department, Sir Charles Gairdner Hospital, Hospital Avenue Nedlands, Western Australia 6009
Country 40288 0
Phone 40288 0
+61412 288 818
Fax 40288 0
+61 8 9346 4375
Email 40288 0

No information has been provided regarding IPD availability
Summary results
No Results