The neonatal jaundice discussion and the use of transcutaneous bilirubinometers has raised some interesting issues.

 

A recent paper from the Mayo Clinic  “BiliChek transcutaneous bilirubin meter overestimates serum bilirubin as measured by the Doumas reference method ( Clin Biochem 2010; 43; 1009 -12 )” contains some important analytical information on the reliablity of this device.

 

One important consideration is that the laboratory comparison assay used in this paper was first aligned with the Doumas reference assay in Stan Lo’s laboratory in Wisconsin to ensure that the bias in the routine laboratory assay was minimal.  

 

Some interesting findings were as follows:

 

• The within-run imprecision of BiliChek was approximately five times greater than the laboratory assay, raising questions on the ability of BiliChek to reliably detect clinically significant changes in bilirubin concentration.  The BiliChek had an SD of 18-19 umol/L around replicate measurements.

 

• For 115 neonates, 95% of results by BiliChek were between 5 and 94 umol/L higher than the laboratory assay ( mean bias + 50 umol/L ).  Three samples with concentrations below 240 umol/L had results around 100 umol/L higher by BiliChek.

 

• Although this positive bias ensures BiliChek has good sensitivity for detecting high/high intermediate risk of potentially dangerous bilirubin concentrations using the Bhutani nomogram, more than 50% of results were “incorrectly” classified as potentially dangerous versus the laboratory assay.

 

Thus pain and risk of infection in the neonate using a laboratory assay must be balanced against the performance limitations of BiliChek.

 

Given the above, it would be interesting to hear from others whether they believe the NICE guidelines would be suitable for their own child in the situations where transcutaneous bilirubin measurements are recommended.

 

It should also be acknowledged that many laboratory assays have more total error than desirable ( see ref 10 in the above paper ).

 

Michael Peake ( recently retired )

Flinders Medical Centre

Bedford Park

South Australia

Australia.

 

 

 

Not withstanding that. The trans bili will frequently need confirming by the lab so the baby will have to bled anyway. Moreover other tests are often required with the bili so a bleed is still needed.

 

Then of course we get into the governance issues regarding the POCT device – training, competencies, training updates, quality checks, maintenance, record keeping, laboratory verification of borderline results etc etc. Horror stories abound with regard to POCT devices – getting this test wrong is potentially catastrophic, therefore I for one would prefer to have my babys’ bili checked by a “proper” method and will therefore not be advocating buying lots of transcutaneous bilirubinometers.

 

Best wishes to all.

 

Ian

 

 

 

 

 

**************************************************************************************
Prof. Tim Reynolds
Consultant Chemical Pathologist
Burton Hospitals NHS Foundation Trust
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-----Original Message-----
From: Clinical biochemistry discussion list [mailto:[log in to unmask]] On Behalf Of Ian Barlow
Sent: 06 September 2010 17:21
To: [log in to unmask]
Subject: Re: Neonatal Jaundice

But Trans Bili should only be used when babies are 35 weeks or more and are therefore unlikely to weigh 1000g. Moreover, when was the last time we needed to get 8ml of blood to check a bili?

 

 

 

 

---

From: Clinical biochemistry discussion list [mailto:[log in to unmask]] On Behalf Of Reynolds Tim
Sent: 06 September 2010 17:12
To: [log in to unmask]
Subject: Re: Neonatal Jaundice

 

Because taking blood samples from neonates causes significant pain and iatrogenic blood loss. If these can be avoided to a large extent this is of benefit to the infant.

 

For a 1000g fetus, 8mL of blood is the equivalent of 1 pint blood loss from an adult.

 

60% of the most painful procedures applied to neonates are related to collecting samples. Neurobehavioral studoes show that these stimuli have a long-lasting effect on the responses to stimuli of oinfamts that have been on a NNU.

 

 

 

**************************************************************************************
Prof. Tim Reynolds
Consultant Chemical Pathologist
Burton Hospitals NHS Foundation Trust
work tel: 01283 511511 ext 4035
work fax: 01283 593064
work email: [log in to unmask]
home email: [log in to unmask]
work URL: www.burtonhospitals.nhs.uk
This e-mail, and any files transmitted with it, are confidential and intended solely for the use of the individual to whom it is addressed. If you are not the intended recipient please destroy this message, delete any copies held on your systems, and notify the sender immediately. You should not retain copy or use this e-mail for any purpose, nor disclose all or any part of its content to any other person. If you have received this e-mail in error, please notify me on 01283 511511 Ext 4035

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-----Original Message-----
From: Clinical biochemistry discussion list [mailto:[log in to unmask]] On Behalf Of Ian Barlow
Sent: 06 September 2010 17:03
To: [log in to unmask]
Subject: Re: Neonatal Jaundice

Why do we waste precious NHS resources on equipment that provides an inferior test result, (is recommended to be checked by the lab), and does not need to be done with critical urgency?

 

Ian

 

---

From: Clinical biochemistry discussion list [mailto:[log in to unmask]] On Behalf Of Jonathan Kay
Sent: 06 September 2010 16:09
To: [log in to unmask]
Subject: Re: Neonatal Jaundice

 

Yes, we're buying lots of transcutaneous bilirubinometers. Unfortunately it looks as if the first tranche won't have computerised communications available.

 

Does any one have a project or system that does?

 

(Our guess is that the CLT workload will initially go up, then go down... )

 

Jonathan

 

 

On 6 Sep 2010, at 15:55, O'Connor John (Royal Devon and Exeter Foundation Trust) wrote:

 

Dear Collective

 

Are labs following the recently published guideline on neonatal jaundice published in May this year?

 

Quite interesting that TC Bilirubin seems to be first line choice of measurement

 

BW John

 

http://www.nice.org.uk/nicemedia/live/12986/48678/48678.pdf

• use a transcutaneous bilirubinometer in babies with a gestational age of

35 weeks or more and postnatal age of more than 24 hours

• if a transcutaneous bilirubinometer is not available, measure the serum

bilirubin

• if a transcutaneous bilirubinometer measurement indicates a bilirubin

level greater than 250 micromol/litre check the result by measuring the

serum bilirubin

• always use serum bilirubin measurement to determine the bilirubin

level in babies with jaundice in the first 24 hours of life

• always use serum bilirubin measurement to determine the bilirubin

level in babies less than 35 weeks gestational age

• always use serum bilirubin measurement for babies at or above the

relevant treatment threshold for their postnatal age, and for all

subsequent measurements

• do not use an icterometer.

 

The important bit is at the end

Research recommendation

What is the comparative accuracy of the Minolta JM-103 and the BiliChek when compared

to serum bilirubin levels in all babies?

Why this is important

Evidence: The accuracy of transcutaneous bilirubinometers (Minolta JM-103 and BiliChek)

has been adequately demonstrated in term babies below treatment levels (bilirubin

< 250 micromol/litre). New research is needed to evaluate the accuracy of different

transcutaneous bilirubinometers in comparison to serum bilirubin levels in all babies.

Population: Babies in the first 28 days of life. Subgroups to include preterm babies, babies

with dark skin tones, babies with high levels of bilirubin and babies after phototherapy.

Exposure: Bilirubin levels taken from different transcutaneous bilirubinometers. Comparison:

Bilirubin levels assessed using serum (blood) tests. Outcome: Diagnostic accuracy (sensitivity,

specificity, positive predictive value, negative predictive value), parental anxiety, staff and

parental satisfaction with test and cost effectiveness. Time stamp: Sept 2009

 

 

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------ACB discussion List Information-------- This is an open discussion list for the academic and clinical community working in clinical biochemistry. Please note, archived messages are public and can be viewed via the internet. Views expressed are those of the individual and they are responsible for all message content. ACB Web Site http://www.acb.org.uk Green Laboratories Work http://www.laboratorymedicine.nhs.uk List Archives http://www.jiscmail.ac.uk/lists/ACB-CLIN-CHEM-GEN.html List Instructions (How to leave etc.) http://www.jiscmail.ac.uk/ ------ACB discussion List Information-------- This is an open discussion list for the academic and clinical community working in clinical biochemistry. Please note, archived messages are public and can be viewed via the internet. Views expressed are those of the individual and they are responsible for all message content. ACB Web Site http://www.acb.org.uk Green Laboratories Work http://www.laboratorymedicine.nhs.uk List Archives http://www.jiscmail.ac.uk/lists/ACB-CLIN-CHEM-GEN.html List Instructions (How to leave etc.) http://www.jiscmail.ac.uk/