Guest guest Posted April 29, 2005 Report Share Posted April 29, 2005 At 12:56 AM 4/29/05, Chas wrote: >: > >Even if you were able to average a continuous set of readings from the >previous three months, it still might not equal the test results of the >lab. Often times, HbA1c readings are weighted more heavily towards the >events of the most recent few weeks, while those of the earliest month >or so are discounted. I decided to do some Googling and found my own reference. Of COURSE my previous mail had already gone off into cyberspace. Here's what I found: >Glucose binds slowly to hemoglobin A, forming the A1c subtype. The >reverse reaction, or decomposition, proceeds relatively slowly, so any >buildup persists for roughly 4 weeks. Because of the reverse reaction, >the actual HbA1c level is strongly weighted toward the present. Some of >the HbA1c is also removed when erythrocytes (red blood cells) are >recycled after their normal lifetime of about 90-120 days. These >factors combine so that the HbA1c level represents the average bG level >of approximately the past 4 weeks, strongly weighted toward the most >recent 2 weeks. It is almost entirely insensitive to bG levels more >than 4 weeks previous. This came from http://www.faqs.org/faqs/diabetes/faq/part2/ and is Copyright 1993-2003 by Reid. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 29, 2005 Report Share Posted April 29, 2005 At 12:56 AM 4/29/05, Chas wrote: >: > >Even if you were able to average a continuous set of readings from the >previous three months, it still might not equal the test results of the >lab. Often times, HbA1c readings are weighted more heavily towards the >events of the most recent few weeks, while those of the earliest month >or so are discounted. I decided to do some Googling and found my own reference. Of COURSE my previous mail had already gone off into cyberspace. Here's what I found: >Glucose binds slowly to hemoglobin A, forming the A1c subtype. The >reverse reaction, or decomposition, proceeds relatively slowly, so any >buildup persists for roughly 4 weeks. Because of the reverse reaction, >the actual HbA1c level is strongly weighted toward the present. Some of >the HbA1c is also removed when erythrocytes (red blood cells) are >recycled after their normal lifetime of about 90-120 days. These >factors combine so that the HbA1c level represents the average bG level >of approximately the past 4 weeks, strongly weighted toward the most >recent 2 weeks. It is almost entirely insensitive to bG levels more >than 4 weeks previous. This came from http://www.faqs.org/faqs/diabetes/faq/part2/ and is Copyright 1993-2003 by Reid. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 29, 2005 Report Share Posted April 29, 2005 At 12:56 AM 4/29/05, Chas wrote: >: > >Even if you were able to average a continuous set of readings from the >previous three months, it still might not equal the test results of the >lab. Often times, HbA1c readings are weighted more heavily towards the >events of the most recent few weeks, while those of the earliest month >or so are discounted. I decided to do some Googling and found my own reference. Of COURSE my previous mail had already gone off into cyberspace. Here's what I found: >Glucose binds slowly to hemoglobin A, forming the A1c subtype. The >reverse reaction, or decomposition, proceeds relatively slowly, so any >buildup persists for roughly 4 weeks. Because of the reverse reaction, >the actual HbA1c level is strongly weighted toward the present. Some of >the HbA1c is also removed when erythrocytes (red blood cells) are >recycled after their normal lifetime of about 90-120 days. These >factors combine so that the HbA1c level represents the average bG level >of approximately the past 4 weeks, strongly weighted toward the most >recent 2 weeks. It is almost entirely insensitive to bG levels more >than 4 weeks previous. This came from http://www.faqs.org/faqs/diabetes/faq/part2/ and is Copyright 1993-2003 by Reid. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 29, 2005 Report Share Posted April 29, 2005 http://www.faqs.org/faqs/diabetes/faq/part2/section-9.html What's HbA1c and what's it mean? Hb = hemoglobin, the compound in the red blood cells that transports oxygen. Hemoglobin occurs in several variants; the one which composes about 90% of the total is known as hemoglobin A. A1c is a specific subtype of hemoglobin A. The 1 is actually a subscript to the A, and the c is a subscript to the 1. " Hemoglobin " is also spelled " haemoglobin " , depending on your geographic allegiance. Glucose binds slowly to hemoglobin A, forming the A1c subtype. The reverse reaction, or decomposition, proceeds relatively slowly, so any buildup persists for roughly 4 weeks. Because of the reverse reaction, the actual HbA1c level is strongly weighted toward the present. Some of the HbA1c is also removed when erythrocytes (red blood cells) are recycled after their normal lifetime of about 90-120 days. These factors combine so that the HbA1c level represents the average bG level of approximately the past 4 weeks, strongly weighted toward the most recent 2 weeks. It is almost entirely insensitive to bG levels more than 4 weeks previous. In non-diabetic persons, the formation, decomposition and destruction of HbA1c reach a steady state with about 3.0% to 6.5% of the hemoglobin being the A1c subtype. Most diabetic individuals have a higher average bG level than non-diabetics, resulting in a higher HbA1c level. The actual HbA1c level can be used as an indicator of the average recent bG level. This in turn indicates the possible level of glycation damage to tissues, and thus of diabetic complications, if continued for years. Interpreting HbA1c values can be tricky for several reasons. See the following section for more details. The source is not listed S Wilkinson Rome, NY I do not pretend to know what many ignorant men are sure of. Clarence Darrow -----Original Message----- Chas wrote: >Often times, HbA1c readings are weighted more heavily towards the >events of the most recent few weeks, while those of the earliest month >or so are discounted. I've heard that before on this list and mentioned it to my nurse practitioner. She said she'd never heard of that and asked if I had any references for it. So I'll ask you if you have some references. -=sky=- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 29, 2005 Report Share Posted April 29, 2005 http://www.faqs.org/faqs/diabetes/faq/part2/section-9.html What's HbA1c and what's it mean? Hb = hemoglobin, the compound in the red blood cells that transports oxygen. Hemoglobin occurs in several variants; the one which composes about 90% of the total is known as hemoglobin A. A1c is a specific subtype of hemoglobin A. The 1 is actually a subscript to the A, and the c is a subscript to the 1. " Hemoglobin " is also spelled " haemoglobin " , depending on your geographic allegiance. Glucose binds slowly to hemoglobin A, forming the A1c subtype. The reverse reaction, or decomposition, proceeds relatively slowly, so any buildup persists for roughly 4 weeks. Because of the reverse reaction, the actual HbA1c level is strongly weighted toward the present. Some of the HbA1c is also removed when erythrocytes (red blood cells) are recycled after their normal lifetime of about 90-120 days. These factors combine so that the HbA1c level represents the average bG level of approximately the past 4 weeks, strongly weighted toward the most recent 2 weeks. It is almost entirely insensitive to bG levels more than 4 weeks previous. In non-diabetic persons, the formation, decomposition and destruction of HbA1c reach a steady state with about 3.0% to 6.5% of the hemoglobin being the A1c subtype. Most diabetic individuals have a higher average bG level than non-diabetics, resulting in a higher HbA1c level. The actual HbA1c level can be used as an indicator of the average recent bG level. This in turn indicates the possible level of glycation damage to tissues, and thus of diabetic complications, if continued for years. Interpreting HbA1c values can be tricky for several reasons. See the following section for more details. The source is not listed S Wilkinson Rome, NY I do not pretend to know what many ignorant men are sure of. Clarence Darrow -----Original Message----- Chas wrote: >Often times, HbA1c readings are weighted more heavily towards the >events of the most recent few weeks, while those of the earliest month >or so are discounted. I've heard that before on this list and mentioned it to my nurse practitioner. She said she'd never heard of that and asked if I had any references for it. So I'll ask you if you have some references. -=sky=- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 29, 2005 Report Share Posted April 29, 2005 http://www.faqs.org/faqs/diabetes/faq/part2/section-9.html What's HbA1c and what's it mean? Hb = hemoglobin, the compound in the red blood cells that transports oxygen. Hemoglobin occurs in several variants; the one which composes about 90% of the total is known as hemoglobin A. A1c is a specific subtype of hemoglobin A. The 1 is actually a subscript to the A, and the c is a subscript to the 1. " Hemoglobin " is also spelled " haemoglobin " , depending on your geographic allegiance. Glucose binds slowly to hemoglobin A, forming the A1c subtype. The reverse reaction, or decomposition, proceeds relatively slowly, so any buildup persists for roughly 4 weeks. Because of the reverse reaction, the actual HbA1c level is strongly weighted toward the present. Some of the HbA1c is also removed when erythrocytes (red blood cells) are recycled after their normal lifetime of about 90-120 days. These factors combine so that the HbA1c level represents the average bG level of approximately the past 4 weeks, strongly weighted toward the most recent 2 weeks. It is almost entirely insensitive to bG levels more than 4 weeks previous. In non-diabetic persons, the formation, decomposition and destruction of HbA1c reach a steady state with about 3.0% to 6.5% of the hemoglobin being the A1c subtype. Most diabetic individuals have a higher average bG level than non-diabetics, resulting in a higher HbA1c level. The actual HbA1c level can be used as an indicator of the average recent bG level. This in turn indicates the possible level of glycation damage to tissues, and thus of diabetic complications, if continued for years. Interpreting HbA1c values can be tricky for several reasons. See the following section for more details. The source is not listed S Wilkinson Rome, NY I do not pretend to know what many ignorant men are sure of. Clarence Darrow -----Original Message----- Chas wrote: >Often times, HbA1c readings are weighted more heavily towards the >events of the most recent few weeks, while those of the earliest month >or so are discounted. I've heard that before on this list and mentioned it to my nurse practitioner. She said she'd never heard of that and asked if I had any references for it. So I'll ask you if you have some references. -=sky=- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 30, 2005 Report Share Posted April 30, 2005 Gretchen et al.: Does anyone know how to determine your 'personal red blood cell recycling rate'? Its probably doesn't represent *that* much of an improvement, but knowing the number would also give a better idea how to improve the accuracy of A1c tests simply by adjusting their timing .... - Chas > > If one wanted to know what an A1c would be, based on continuous > readings, it should be fairly simple to come up with a formula that > would do the weighting. I think some of the diabetes software programs > come up with estimates. I don't know if they do weighting or not. > > Gretchen > > > __________________________________________________ Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 30, 2005 Report Share Posted April 30, 2005 Gretchen et al.: Does anyone know how to determine your 'personal red blood cell recycling rate'? Its probably doesn't represent *that* much of an improvement, but knowing the number would also give a better idea how to improve the accuracy of A1c tests simply by adjusting their timing .... - Chas > > If one wanted to know what an A1c would be, based on continuous > readings, it should be fairly simple to come up with a formula that > would do the weighting. I think some of the diabetes software programs > come up with estimates. I don't know if they do weighting or not. > > Gretchen > > > __________________________________________________ Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 30, 2005 Report Share Posted April 30, 2005 Gretchen et al.: Does anyone know how to determine your 'personal red blood cell recycling rate'? Its probably doesn't represent *that* much of an improvement, but knowing the number would also give a better idea how to improve the accuracy of A1c tests simply by adjusting their timing .... - Chas > > If one wanted to know what an A1c would be, based on continuous > readings, it should be fairly simple to come up with a formula that > would do the weighting. I think some of the diabetes software programs > come up with estimates. I don't know if they do weighting or not. > > Gretchen > > > __________________________________________________ Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 30, 2005 Report Share Posted April 30, 2005 > Does anyone know how to determine your 'personal red blood cell > recycling rate'? You could inject yourself with radioactive hemoglobin and then plot the decay of labeled red blood cells with time. There are clearly ways, but nothing you would want to do at home. Gretchen Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 30, 2005 Report Share Posted April 30, 2005 > Does anyone know how to determine your 'personal red blood cell > recycling rate'? You could inject yourself with radioactive hemoglobin and then plot the decay of labeled red blood cells with time. There are clearly ways, but nothing you would want to do at home. Gretchen Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 30, 2005 Report Share Posted April 30, 2005 > Does anyone know how to determine your 'personal red blood cell > recycling rate'? You could inject yourself with radioactive hemoglobin and then plot the decay of labeled red blood cells with time. There are clearly ways, but nothing you would want to do at home. Gretchen Quote Link to comment Share on other sites More sharing options...
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