Optimal and Inappropriate Laboratory Testing For Assessing Insulin Homeostasis

Majid Ali, M.D.

Grievous Errors in Insulin Testing


 

What Is Optimal Laboratory Insulin Testing?

What Are Commonly Made Grievous Insulun Testing Errors?

 Optimal laboratory testing for assessing insulin homeostasis is to use tests that directly and specifically assess various aspects of insulin homeostasis. Inappropriate laboratory testing for assessing insulin homeostasis is to use tests that do not directly and specifically assess various aspects of insulin homeostasis.
 
Examples of optimal laboratory tests for insulin homeostasis are measurement of blood insulin concentration with fasting blood samples and timed samples obtained after a standard glucose challenge. Examples of inappropriate insulin tests are fasting blood glucose level, two-hours post-prandial blood glucose level, and A1c since these tests are test for glycemic status and not for assessing insulin homeostasis. 

Grievous Errors In Insulin Laboratory Tests
 
I recognize the following commonly made grievous errors in laboratory assessment of insulin homeostasis. Regrettably, these errors are deemed optimal standards for many doctors. 
 
1.   Blood insulin tests are done on randomly drawn blood tests (Results of such tests                              simply cannot be interpreted).
2.   The epidemic prevalences of hyperinsulinism of varying degrees are near-completely                     ignored in clinical medicine and insulin tests are simply not done (Table 2). 
3.   Tests for blood  sugar levels are done as substitutes for insulin tests. Glucose tests                            and others for glycemic status simply are not insulin tests.
4.   Laboratories use wholly inappropriate references ranges for blood insulin concentrations (See Table 2 for specifics). 
5.   Cut-off points for blood insulin concentrations determined with timed, post-glucose-                   challenge are not based on real insulin testing data.
6.   Insulin is the primary pro-weight gain and pro-obesity hormone, and yet insulin tests                 are done in weight loss and obesity programs. 
7.  Gestational diabetes is an insulin disorder before it becomes a glucose (sugar)                                 disorder. Insulin tests are not done for gestational diabetes.
8.  Insulin in excess is a potent the primary pro-weight gain and pro-obesity hormone,                       and yet insulin tests are done in weight loss and obesity programs. 
9. Insulin in excess is proinflammatory, pro-infections, pro-cancer, pro-premature aging,                 and pro-degenerative disorders and yet insulin tests are seldom, if ever, done by                 most doctors. 
10. Indeed, insulin in excess increases the risk of and fans the fires of all nearly chronic                  diseases 

Two Subtypes of Type 2 Diabetes: T2D Subtype A and T2D Subtype B
In 2014, I recognized the need to subtype Type 2 diabetes (T2D) into two T2D subtypes:
                              T2D subtype A
                               T2D subtype B
Diabetes is a two-faced disease, one with insulin toxicity and the other with insulin depletion: this diabetes duality in itself is most revealing. Below we present five sets of illustrative insulin and glucose profile taken from our original communication to make and illustrate our main points, which are presented and its full clinical implications considered in a separate chapter For the first five, ten or more years, the disease is characterized by rising blood sugar levels accompanied by increasing blood concentrations of insulin (hyperinsulinism aptly designated insulin toxicity). In the later years, T2D is characterized by rising blood sugar levels accompanied by falling insulin levels, this is the stage of insulin depletion (see Tables 1.1 and 1.2 for details).
Table 1. Insulin Homeostasis Categories in 506 Study Subjects Without Type 2 Diabetes
Insulin Category*
Percentage of Subgroup
Mean Peak Glucose  mg/dL
(mmol/mL)
Mean Peak Insulin (uIU/mL)
Exceptional Insulin Homeostasis.N 12**
1.7%
110.2     (6.12)
14.3
Optimal Insulin Homeostasis N =126
24.9 %
121.2     (6.73)
26.7
Hyperinsulinism, Mild                N =197
38.9 %
136.5   (7.58)
58.5
Hyperinsulinism,  Moderate       N =134
26.5 %
147.0    (8.16)
109.1
Hyperinsulinism,  Severe             N =  49
9.7 %
150.0    (8.33)
(less than time and a half higher) 
231.0
(nearly 17 times higher)
#   Correlation coefficient, r value, for means of peak glucose and insulin levels in the five insulin categories is 0.84.
*Criteria for classification: (1) Exceptional insulin homeostasis, a subgroup of optimal insulin homeostasis with fasting insulin concentration of <2 uIU/mL and mean peak insulin concentration of <20; (2) optimal insulin homeostasis, peak insulin <40 accompanied by unimpaired glucose tolerance; (3) mild
 


Table 2.  Insulin Reference Ranges  in uIU/mL of Six Laboratories in New York Metropolitan Area*
 Laboratory
 Fasting
 1 Hr
 2 Hr
 3 Hr
 Laboratory 1
1.9 – 23
8  –  112
 5 – 35
 Not Reported
 Laboratory 2
 2.6 – 24.9
 0.0  – 121.9
 0.0 – 163.5
 Not Reported
 Laboratory 3 
 2.6 – 24.9
 8  –  112
 5  –  55
 3  –  20
 Laboratory 4
 6  – 27
 20  –  120
 18  –  56
 8  –  22
 Laboratory  5
 00  – 30
 30  –  200
 40  – 300
 50  – 150
 Laboratory 6
 Does not include insulin ranges in the report. Instead it includes the following note: Insulin analogues may demonstrate non-linear cross-reactivity in this essay. Interpret results accordingly.**
*Upper and lower limits of laboratory reference ranges for blood insulin concentration determined following a Standard 75-gram glucose challenge.
**Personal communications with clinicians revealed that they do not find this laboratory note to be satisfactory in their clinical decision-making.

Grievous Errors in Insulin Testing

First Grievous Error: Believing That Diabetes (T2D) Is a Sugar (Glucose) Problem 
The first grievous error of considering insulin insufficiency as the cause of T2D has misled generations of doctors, leading to the mistreatment of hundreds of millions of people with prediabetes and T2D. In reality, hyperinsulinism predates T2D for five to ten or more years, although the study of insulin homeostasis is not deemed a standard of care for health preservation and disease prevention and/or control. Indeed, it is not taught in medical schools or on hospital wards, even where there are patients with suspected or diagnosed diabetes. The neglect of this core aspect of insulin dysregulation results in: (1) delayed diagnosis of T2D, and (2) as we document conclusively, the failure to detect and address long-established metabolic, inflammatory, immune, cardiovascular, and neurological consequences of insulin hyperinsulinism (Bahi-Buisson et al., 2008; Dandona, Aljada and Bandyopadhyay, 2004; IDFDA, 2016; Khan, Hull and Utzschneider, 2006; Shoelson, Lee and Goldfine, 2006; Shulman, 2014; Wellen and Hotamisligil, Shargill and Spiegelman,2005). Notable in this context is the recent documentation of hyperinsulinism in autism and pediatric dysautonomia (Ali, 2017a), which is discussed in chapter 6.
During the years of excess insulin – hyperinsulinism, or more appropriately insulin toxicity – widespread damage is inflicted in nearly all cell populations in the body. There is a profound irony here.  The very definitions of T1D and T2D lays bare the falsehood of the prevailing belief, the former being a state of near-complete absence of insulin in the blood while the latter for years is accompanied by raised blood insulin concentrations (as documented in Table 1.2). To add to the irony of this, consider the definition of insulin from the website of Merriam Webster Dictionary (March 15, 2017) reproduced verbatim here:
a protein pancreatic hormone secreted by the beta cells of the islets of Langerhans that is essential especially for the metabolism of carbohydrates and the regulation of glucose levels in the blood and that when insufficiently  produced results in diabetes mellitus …and that when insufficiently  produced [insulin] results in diabetes mellitus!
Consequently, it is not surprising that this utterly false notion of T2D caused by insulin insufficiency has become so deeply entrenched in public consciousness? The enduring belief of medical and nursing communities in this misleading dogma is of great concern. The key question is why has this definition not been previously challenged by the medical community?
To bring this grievous error into yet sharper focus, T1D is an acute-onset type disease usually occurring in children, characterized by near-complete absence of insulin-producing capacity of the pancreas gland. By contrast, T2D develops insidiously and, until recently, nearly always developed in adults. The blood insulin concentrations begin to fall after decades of insulin waste that occurs during the hyperinsulinism phase of the disease: this is what medical students learn in classrooms and on medical wards and  what nurses learn in nursing schools. Then the medical tragedy happens. Simple blood tests, for determining blood insulin concentrations to assess the state of insulin homeostasis of individual patients, is not considered a standard of care in any medical specialty or general practice. This disturbing notion of T2D being rooted in insulin insufficiency persists and so the hazards of insulin toxicity go unrecognized.

Second Grievous Error
Neglect of a Specific Quantitative and Modifier Marker
 The Third Grievous Error: Absurd Laboratory Insulin References Ranges
The third grievous error concerns laboratory reference ranges for blood insulin concentrations reported by most university hospital and nationwide commercial laboratories. Rather than guide clinicians interested in the study of insulin dysregulation in their patients, clinical pathologists and laboratory professionals have for decades compounded the problem of neglected hyperinsulinism. Table 1.3 displays wide variations in the lower and upper limits in the reference ranges for fasting and post-glucose challenge blood insulin concentrations employed by six major laboratories in the New York City metropolitan area. The variation in insulin reference ranges invariable invites skepticism, with photographs of actual laboratory reports on the web (www.alidiabetes.org). Note that laboratory 1 reports a range of 5-35 for 2-hour blood insulin level while laboratory 5 reports of range of 40-300 for the sample blood sample: while laboratory 1 reports a range of 5-35 for 2-hour blood insulin level. Further, laboratory 5 reports of range of 40-300 for the sample blood sample, while laboratory 2 reports a range of 0.0 to 121.9 and laboratory 4 reports 20-120 for the same blood sample. It is difficult to imagine a parallel for this level of absurdity in the entire field of laboratory medicine.

Cut-off Points for Optimal Insulin Homeostasis and Degrees of Hyperinsulinism
Our selection of the peak insulin value of <40 mIU/mL as the cut-off point for optimal insulin homeostasis in our survey of prevalence of hyperinsulinism in New York (see Table 1.1), was based on a preliminary review of the first 50 sets of insulin and glucose profiles (Ali et al., 2017a). We opted for cut-off points for hyperinsulinism stratification based on doubling of the levels (to <80, <160, and >160 uIU/mL for mild, moderate, and severe hyperinsulinism) with two considerations: (1) are these cut-off points appropriate for this study, and (2) do they provide a frame of reference for future investigations of diverse aspects of insulin homeostasis and hyperinsulinism-to-T2D progression? There are a number of other issues that need to be considered in this context: (1) what constitutes optimal insulin homeostasis, (2) what should the insulin cut-off point be, as there is no agreement within the relevant literature, (3) no adverse effects of low insulin levels when accompanied by unimpaired glucose tolerance have been reported, and (4) Hyperinsulinism and the metabolic syndrome are commonly spoken in the same breath,  explicitly or implicitly referring to them as the two faces of the same coin. However, there is a crucial difference between the two, the peak insulin level and other features of three-hour insulin and glucose profiles provide clinicians with  specific and quantitative cut-off  points for detecting and stratifying hyperinsulinism but no such criteria have been established for the metabolic syndrome. In addition, three-hour insulin and glucose profiles shed light on other aspects of glycemic status and insulin homeostasis, some of which are presented later in this chapter.
A subgroup of twelve participants was designated ‘exceptional insulin homeostasis’ for two reasons: (1) they showed an extremely low fasting insulin value of <2 uIU/mL (mean 14.3 uIU/mL) and peak insulin concentrations <20 uIU/mL accompanied by unimpaired glucose tolerance, and (2) ten of the twelve had no family history of diabetes (parents, siblings, grandparents, children, uncles or aunts), while the mother of the eleventh subject developed T2D in the closing months of her life at age 74 and both parents of the twelfth subject had T2D. This subgroup appears to reflect ideal metabolic efficiency of insulin in the larger evolutionary context.

Shifting Focus from Glucose Testing to Insulin Testing
As reported in the preface, the much higher rate of hyperinsulinism observed in New York’s general population compared to rates of T2D in India (Kaveeshwar and Cornwell, 2014) and China (Xu et al., 2013), provides strong support for the view that there is a need to shift focus from glucose testing to insulin testing for stemming global tides of hyperinsulinism and T2D. A crucial point in this context is that the data published in the Indian and Chinese studies was derived from glucose testing, whereas our insulin database was derived exclusively from direct insulin testing, with measurements of post-glucose challenge blood insulin concentrations with sequential and timed blood samples.
Here we point out that the insulin and glucose profiles presented in this and other chapters shed light on the full spectra of insulin homeostasis, hyperinsulinism and related patterns of insulin dysfunction, for example insulin spikes followed by hypoglycemic episodes which create hunger for foods that create yet more sugar spike. Therefore the insulin and glucose profiles presented in Tables 1.4-1.8 in this (and numerous in other chapters) require that the data be considered in light of the clinical context as well as looking through the kaleidoscopic prisms of molecular biology of oxygen Ali, 2000, 2002, 2004a, 005a, 2007, 2009a, 2011), oxygen model of hyperinsulinism (Ali, 2014a) and oxygen model of T2D (Ali, 2001). As for co-morbidities of the hyperinsulinism-T2D continuum (metabolic, inflammatory, immune, infectious, cardiovascular, neurological, developmental, gut-microbiota-related, differentiative, and degenerative), we do not recognize any  inconsistencies between our observations and inferences and those of earlier workers (Nath, Heemels and Anson, 2006; Nichols, 2012; Patti et al., 2003; Saltiel and Kahn, 2001; Scherer, 2005; Stanley, 2016; Turnbaugh, 20

 


Table 3. Insulin Homeostasis Categories in 178 Study Subjects With Type 2 Diabetes
Insulin Category
Percentage of Subgroup
Mean Peak Glucose, mg/dL
(mmol/mL)
Mean Peak Insulin (uIU/mL)
Diabetic Hyperinsulinism, Mild              N =  53
29.0%
252.0   (14.00)
55.4
Diabetic Hyperinsulinism, Moderate    N =  42
24.0%
242.1   (13.45)
112.4
Diabetic Hyperinsulinism, Severe          N =  24
13.9%
224.6   (12.47)
298.0
Diabetic  Insulin Deficit                             N =  59
33.1%
294.0    (16.33)
22.9
Illustrative Case Studies of Insulin Responses to Glucose Challenge
Tables 4 to 8 present five illustrative sets of insulin and glucose profiles with brief clinical notes. The insulin profiles in Tables 4 and 8  represent the two extremes of insulin peaks (18 uIU/mL and 718.2 uIU/mL) encountered in this survey. The first of the two profiles (Table 4) is reflective of ideal metabolic efficiency of insulin in a larger evolutionary perspective of energy economy in the body. Notable findings here are: (1) a very low fasting insulin level of <2 uIU/mL reflecting efficient insulin conservation during the fasting state; (2) low insulin peak value (18 uIU/mL) indicating high insulin efficiency following a substantial glucose challenge; and (3) a very low insulin level in the 3-hour sample (<2 uIU/mL) reflects optimal beta cell response to glucose level falling below the fasting level.
 
Table 4. Example of Insulin and Glucose Profiles In Exceptional Insulin Homeostasis Category*
 
Fasting
½ Hr
1 Hr
2 Hr
3 Hr
Insulin uIU/mL
<2
18
14
4
<2
Glucose mg/mL  (mmol/L)
77     (4.27)
168   (9.33)
109      (6.05)
74       (4.11)
59    (2.88)
*The Patient,  A  60-Yr-Old 5’ 7” Man Weighing 138 lbs. Presented for a Wellness Assessment. He Was Considered to be in Excellent Health By Clinical and Laboratory Evaluation Criteria.
Table 5.  Severe Hyperinsulinemia in A Subject With Previously Undiagnosed Type 2 Diabetes*
 
Fasting
½ Hr
1 Hr
2 Hr
3 Hr
Insulin uIU/mL
23.8
19.3
36.9
114.7
75.2
Glucose mg/mL  (mmol/L)
112     (6.21)
158   (8.77)
214      (11.76)
241    (13.38)
129   (7.16)
* The Patient,  A 64-Yr-Old 5’ 4” Woman Weighing 164 lbs. Presented With Hypothyroidism, History of Coronary Artery Stent Insertions, Fatty Liver, Memory Concerns And Without Previous Diagnosis of Type 2 Diabetes.
Table 6. Hyperinsulinism 18 Years After the Diagnosis of Type 2 Diabetes*
Fasting
½ Hr
1Hr
2Hr
3Hr
Insulin uIU/mL
  12.9
27.2
29.2
36.2
25.4
Glucose mg/mL  (mmol/L)
128      (7.10)
224   (12.43)
278    (15.42)
297    (16.48)
249     (13.81)
*The Patient,  A 74-Yr-Old 5’ 6” Woman Weighing 155 Lbs. Presented With Bronchiectasis, Rheumatoid Arthritis, Prehypertension, and Inhalant Allergy.
Table 7. Brisk Insulin Response With A “Flat” Glucose Tolerance Profile*
Fasting
½ Hr
1Hr
2Hr
3Hr
Insulin uIU/mL
3
23
22
8
<2
Glucose mg/mL  (mmol/L)
72      (3.39)
44     (2.44)
63    (3.49)
58     (3.21)
65   (3.90)
*The Patient,  A 47-Yr.Old  5’ 5” Woman Weighing 170 Lbs. Presented With Polyarthralgia, Recurrent Sinusitis, and Fatigue.
Table 8. Severe Hyperinsulinism In A 13-Yr-Old Girl With Lupus Erythematosus*
Fasting
½  Hr
1Hr
2Hr
3Hr
Insulin uIU/mL
27.9
362.5
424.0
718.2
571.7
Glucose mg/mL  (mmol/L)
      70   (3.88)
  140     (7.77)
   157     (8.71)
   150    (8.33)
   111   (6.16)
Insulin and Glucose Profiles Obtained After Four Months of Robust Integrative Therapies
Insulin uIU/mL
7.2
125.1
238.5
208.0
132.0
Glucose mg/mL  (mmol/L)
81     (4.49)
154   (8.54)
181     (10.04)
130     (7.21)
97      (5.38)
*The Patient,  A 13-Yr-Old Girl With a History of Three Hospitalizations In One Year for Systemic Lupus Erythematosus, Recurrent Pneumonia, Thrombocytopenia, and Severe Optic Neuritis Resulting In Complete Loss of Vision In Right Eye. The Peak Insulin Fell from 718 to 238.5 In Four Months of Robust Integrative Treatment.
 

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