Change in Blood Iron Level

April 8, 2023 11:04 AM

I had my iron levels tested 2 weeks ago and the level of iron in my blood and absorbency were very low. They tested again this week and both were higher than normal. I haven't changed anything in the last 2 weeks, what could cause this? Details inside.

I've been feeling tired for the last few months so my iron levels were tested and found to be low (measured at 20 with 40-150 being normal) and low absorbancy. They tested again two weeks later and my level was 180 with absorbancy higher than normal. I didn't change anything in my diet or supplements. The only supplement I take is a daily women's multivitamin (I've taken this brand for more than 10 years). My doctor asked me to make an appointment to discuss but the next one is 4 weeks out. So, I'm wondering if anyone has any ideas on what could cause this.

posted by entropyiswinning to Health & Fitness (6 answers total)

Lab error on one or both measurements could explain this.

Why did they test you twice within a span of only two weeks? Did your doctor order the second test after seeing the results of the first?
posted by heatherlogan at 12:07 PM on April 8, 2023

Variables:
Was it a venous blood draw both times? [Simple finger prick iron tests, done in clinics and donation centers, can have abnormal results if the finger is squeezed too much -- interstitial fluid dilutes the sample]
Were the two samples taken at the same time of day, and processed by the same lab?
Were you fasting on test days, and if so, for how long?
Does your multivitamin contain iron? What was the timing of that vitamin on testing days?
posted by Iris Gambol at 12:20 PM on April 8, 2023

When my iron levels sometimes tested too low to donate blood, the phlebotomist suggested I eat beef or other iron-rich foods a few days before my donation appointment. Worked like a charm. So perhaps the observed difference in your iron levels is diet-related.
posted by DrGail at 12:26 PM on April 8, 2023

Missed in the earlier answer: if you menstruate, there are fluctuations in iron levels throughout the menstrual cycle.
posted by Iris Gambol at 2:36 PM on April 8, 2023

Response by poster: The tests were done by 2 different labs. Retested because the first test didn't include ferritin level. All other factors were the same between the tests (fasting for both, both venous draws, same time of day). I do not menstruate.
posted by entropyiswinning at 3:04 PM on April 8, 2023

Best answer: I have an illness that means I get blood draws two or three times a month that check my hemoglobin. One time, it was so low that the nurse came out to me in the infusion room to ask how I was feeling. She had already called my doc, who had seen me the day before and said I seemed fine. If my levels had really been that low, it would have been a medical emergency requiring immediate transfusions. They redrew my blood right away to check it again, and the levels were fine.

I talked to a pathologist friend and she explained in technical terms that I can't really recall the reason things like that can happen with blood tests. There's a reason that docs don't generally make treatment decisions based on one test. It's quite possible your levels were never actually that low.
posted by FencingGal at 4:43 PM on April 8, 2023 [1 favorite]