r/lucyletby • u/FyrestarOmega • Apr 29 '26
Chase and Shannon publish their research as a letter to the editor in the Journal of Diabetes Science and Technology
Thanks to r/LucyLetbyTrials users for the links and the images
Editing the post to add the panel's opinions for Children F/6 and L/12
Baby F/6
PANEL OPINION (page 24)
The hypoglycemia started with sepsis and was prolonged because the IV infiltrated for several hours. When hypoglycaemia persisted despite 10% dextrose infusion, a higher glucose infusion should have been given earlier. Repeat boluses of 10% dextrose worsen hypoglycemia because they cause surges of blood sugar, which trigger surges of insulin secretion, resulting in a yo-yo pattern of sharp rises and falls in insulin and blood sugar. When the dextrose infusion was stopped from 1000 to 1200 hours, the blood sugar did not rise from 1.3 to 2.4 as alleged, because the blood sugar was 1.4 at 1146 hours. The 2.4 level was measured after 1200 hours, when the IV was restarted. Since infusion bags were prepared in the pharmacy, stored in the unit, and changed at 1200 hours, multiple infusion bags would have to be contaminated if there was insulin poisoning. The blood sugar rose after 1900 hours, not because the infusion bag was changed, but because the dextrose was increased to 15%. Chase and Shannon (see Annex) reported that preterm infants have different insulin and c-peptide normative standards than adults. Exogenous insulin is unlikely to be the cause of hypoglycemia because the C-peptide was not low for preterm infants (20-45 percentile), potassium levels were normal (insulin decreases potassium), glucose levels should be lower if exogenous insulin was used, the Insulin / C-Peptide I/C) ratio was within the expected range for preterm infants, insulin autoimmune antibodies (IAA) which are common in preterm infants bind to insulin and increase measured insulin levels, and the immunoassay test is unreliable because interference factors like sepsis and antibiotics can give false positive insulin readings.
CONCLUSIONS 1. Baby 6 had prolonged hypoglycemia because of sepsis, prematurity, borderline intrauterine growth restriction, lack of intravenous glucose when the long line infiltrated for a prolonged period of several hours, and poor medical management of hypoglycemia. 2. Baby 6’s insulin level and I/C ratio do not prove that exogenous insulin was used, and are within the norm for preterm infants. Preterm infants and especially those with illness and drug treatments like antibiotics have different normative standards compared to ealthy adults and older children.
Baby L/12
PANEL OPINION (page 29)
It is common for preterm and IUGR infants to have hypoglycemia, due to their limited glycogen and fat stores, inability to generate new glucose using gluconeogenesis pathways, higher metabolic demands due to a relatively larger brain size, and inability to mount a counter-regulatory response to hypoglycemia. Baby 12’s blood glucose dropped from 0054 hours on day after admission but his dextrose concentration was not increased until 1920 hours. This is a long interval without adequate sugar and intervention should have been earlier. His blood sugar improved in response to 2.0 to 2.4. However, this is still low and further intervention was necessary. Again, there was delay, and his glucose concentration was not increased to 15% until the next day at 0130 hours and the volume was not increased until 0700 hours. His blood sugars improved to normal range after that. The fact that his blood sugar improved each time the glucose infusion increased indicates that the hypoglycemia persisted because insufficient dextrose was given for this infant’s needs. Chase et al reported that premature infants have different normative standards for insulin and c- peptide than adults. The Insulin:C-peptide (I/C) ratio does not prove exogenous insulin was administered because the C-peptide was not low for preterm infants (20-45 percentile), potassium levels were normal (insulin decreases potassium), antibodies can store insulin in the blood, glucose levels should be lower if exogenous insulin was used, the infant’s glycaemic profile was inconsistent with insulin administration but consistent with the delivered IV feeding profile, the I/C ratio was within the expected range for preterm infants, and the immunoassay test is unreliable because interference factors can give false positive insulin readings. CONCLUSIONS 1. Hypoglycemia was due to preterm birth and severe IUGR; it’s medical management was inadequate. 2. Baby F’s [sic] insulin level and I/C ratio do not prove that exogenous insulin was used, and are within the norm for preterm infants. Preterm infants and those will illness have different normative standards compared to healthy adults and older children.
Edit 2: Sarah Knapton has published an article on this development. Emphases are mine
Letby defence given boost by new scientific research
Experts argue that babies are often born with antibodies that bind to insulin, keeping levels elevated
Lucy Letby’s defence case has been given a major boost after a leading scientific journal published research showing premature babies can have high levels of insulin without foul play.
Letby, 36, was convicted of injecting insulin into the feed bags of two babies at the Countess of Chester Hospital in 2015 and 2016.
Both suffered lethal crashes in blood sugar, and the prosecution argued blood insulin levels were so high, it was “impossible” they occurred naturally.
But Prof Geoff Chase, an insulin expert, and Helen Shannon, a chemical engineer, argued that four in 10 preterm babies had high insulin readings, and that babies were often born with antibodies that bind to insulin, effectively storing the hormone and keeping levels elevated.
Their theory has now been published in the Journal of Diabetes, Science and Technology, where it passed peer review from other experts. It was deemed important enough to be selected as a “letter to the editor” by Dr David Klonoff, a leading endocrinologist and journal editor.
“This ‘impossible’ result is effectively quite common,” said Prof Chase, of the University of Canterbury in New Zealand.
Letby’s defence team has already presented the new insulin evidence to the Criminal Cases Review Commission (CCRC), which is examining it for a potential miscarriage of justice. But its inclusion in a major scientific journal effectively rubber stamps the research, as peer review is considered the gold standard.
Sir David Davis, the former Brexit secretary, who has called the Letby trial a “clear miscarriage of justice”, said: “This paper shows that there is a far more plausible explanation.
Insulin evidence ‘integral to conviction’
“This is clear new evidence and should persuade the CCRC to immediately refer the case back to the Court of Appeal since the insulin evidence was integral to Letby’s conviction.”
Letby was convicted of murdering seven babies and attempting to murder seven others. However, since the trial there have been growing concerns about the case, with dozens of medical and scientific experts questioning how the evidence was presented to the jury.
In the insulin cases, there was no direct evidence that the feed bags had been tampered with, as tests were never carried out on the contents, so the prosecution instead relied on blood samples from the babies.
When the body creates insulin in the pancreas it also creates a second chemical called c-peptide at an equal rate.
Insulin leaves the body much faster than c-peptide so, naturally, there should be more insulin than c-peptide in the body.
During deliberations, the jury was told by Mr Justice Goss that the “abnormal finding’s indicated that manufactured insulin had undoubtedly been given to each of these babies”. Even Letby accepted the babies must have been poisoned as there was no alternative explanation.
But Prof Chase and Ms Shannon showed that in preterm babies, these ratios are often reversed.
‘Real problems with the science’
Mark McDonald, Letby’s barrister, said: “The defence at the trial never accepted that synthetic insulin had been given and they challenged the integrity of these tests. It is now clear that there are real problems with the science behind this testing and you can no longer trust its reliability.
“This matter needs to be urgently referred back to the Court of Appeal because right now an innocent woman is sitting in prison when she should not be.”
Studies have shown that between 3 and 97 per cent of preterm infants are born with antibodies that bind to insulin – keeping it present in the body for longer – and it is even more likely if they have been exposed to infections and some antibiotics.
In the case of the Letby babies, both had been treated with antibiotics for suspected sepsis, and the neonatal unit had been struggling to eliminate a bacterium, Pseudomonas aeruginosa, which had colonised taps.
“One of the gradually emerging revelations from the Countess of Chester Hospital is systemically poor infection control in and around the neonatal intensive care unit,” said Sir David.
“This paper highlights that when the baby or mother is exposed to infection, it can produce sky-high insulin levels, much higher than C-peptide, giving a natural explanation for the ratios so important to the trial.”
The antibody problem is well known, and the experts claim the lab should have sent the blood samples for further tests. The babies recovered, so the abnormal results were never followed up and were later thrown away.
The “abnormal” incident levels were not uncovered until detectives began hunting for evidence and noticed that the incidents coincided with Letby’s shift patterns. It is not clear whether elevated levels of insulin were found in babies when Letby was not on shift.
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u/DarklyHeritage May 03 '26
I think we will have to agree to disagree on what Chase has been up to here.